Introduction to Psychology - A Gateway to Mind and Behavior

=The Book=

=Chapter 1: Introduction to Psychology and Research Methods=

Psychology - Behave Yourself!
Behavior is anything that someone does. This can include overt behavior, which is directly observable behavior, as well as covert behavior, which is not as easily, directly externally observable, such as dreaming or thinking.

Goals of Psychology:
 * 1) Description of behavior: accurate record of scientific observations
 * 2) Understanding behavior: identify the cause for a certain behavior
 * 3) Prediction of behavior: forecast behavior as reliably as possible
 * 4) Control behavior: alter the conditions which influence behavior

Critical Thinking - Take it with a grain of salt
The basic principles of critical thinking
 * 1) There are few statements which can be deemed true without thorough scientific testing and analysis
 * 2) Critical Thinkers are more occupied with falsifying beliefs and statements than with verifying them. This quest extends even to their own beliefs which will in the end make them more confident in their beliefs since they have survived a whole series of falsification attempts.
 * 3) Never trust that something is true because an 'expert' says it is. Rather try and figure out whether the expert's argumentation is plausible and whether the evidence brought forward is convincing.
 * 4) Always pay attention not only to the quantity but also to the quality of the evidence provided to sustain an argument
 * 5) Always be open-minded but never to the point of becoming gullible, be prepared to think in entirely new ways, but don't be to easily convinced

Uncritical Acceptance Taking something for the truth only because we want to believe that it is true or it would be desirable if it were so.

Confirmation Bias When getting information (reading a text, listening to a podcast, watching the news), we tend to pick out the information which confirms our pre-existing assumptions

The Barnum Effect The inclination to identify with personal descriptions when they are stated in general terms

Scientific Research - How to think like a psychologist
The six elements of the scientific method


 * 1) Making observations
 * 2) Defining a problem
 * 3) Proposing a hypothesis (a possible explanation for a certain behavior)
 * 4) Gathering evidence/ Testing the hypothesis
 * 5) Theory building (theories establish relations between different concepts and facts, taking into account existing data and predicting future results)
 * 6) Publishing results

operational definition - names the exact procedures used to represent a certain otherwise intangible concept. That way covert behavior is defined in terms of overt behavior and by that can be tested and measured scientifically.

A Brief history of psychology - Psychologies family album
stimulus any physical impulse that has an effect on a person and evokes a response

conditioned response a learned reaction to a certain stimulus

Structuralism - the use of introspection to make deductions about sensations and perceptions

Functionalism - mirroring the development of the theory of evolution in biology, the quest to find out how the mind contributed to adapting to an environment

Behaviorism - based on the belief that all human responses are determined by stimuli alone

Gestalt-Psychology - an all encompassing view of sensation and thought, regarding them as whole experiences, not broken into units

Psychoanalytical Psychology - a large part of the mind and of the resulting processes takes part in the unconscious, a lot of which is repressed. every behavior has a cause, which can, however, not be found in external stimuli but rather in the unconscious. Freud as the father of this branch of psychology also created the first form of psychotherapy. Today psychodynamic theories are more common which represent a kind of legacy of Freud's approaches, they still emphasize the importance of internal processes and of the unconsciousness

Humanistic Psychology - focus on subjective human experience, ideals, problems and potential. Belief in the free will of humans, the possibility to choose the direction life is going to take

Psychology Today - Three complementary perspectives on Behavior
Biological Perspective


 * 1) Biopsychological View - behavior is the result of internal physical, chemical and biochemical processes, mechanistic perspective
 * 2) Evolutionary View - behavior is the result of the process of evolution, mechanistic perspective

Psychological Perspective


 * 1) Behavioral View - behavior is shaped by the environment, mechanistic perspective
 * 2) Cognitive View - behavior can be understood in terms of mental processes and information processing, computer-like perspective
 * 3) Psychodynamic View - emphasizes internal processes and hidden and unconscious forces, pessimistic perspective
 * 4) Humanistic View - behavior is directed by the self-image, subjective perceptions of the world and the personal need for growth, positive philosophical view

Sociocultural Perspective


 * 1) Sociocultural View - behavior is influenced by the social and cultural context, interactionist perspective

The Psychology Experiment - Where Cause meets Effect
The three steps of conducting a psychological experiment


 * 1) Manipulate a condition which you suppose has a direct effect on behavior (this condition can also be referred to as variable)
 * 2) Set up two or more groups of subjects which are exactly the same apart from the condition which is being manipulated (the experimental and the control group)
 * 3) Record whether the manipulation did in fact have an impact on the behavior monitored

The different types of variables

→ the experimental groups is exposed only to the independent variable and the control group to exactly the conditions except for the independent variable. By keeping the interfering extraneous variables away from both groups any difference in the dependent variable after the experiment must have been caused by the manipulation of the independent variable. This allows to establish a clear Cause and Effect relation. In order to obtain valid results they must be statistically significant, which means that it has to be highly unlikely that the results obtained in the experiment were only obtained by chance or coincidence.
 * 1) Independent variables are the conditions which are suspected to have an impact on the monitored behavior. They are manipulated by the experimenter.
 * 2) Dependent variables is the behavior which is being monitored and on which the manipulated conditions are expected to have an impact.
 * 3) Extraneous variables are all those conditions which the experimenter wants to prevent from having an effect on the result.

To ensure a representative sample of people in both groups the assignment to both groups is randomized.

Meta-Analysis - the synthesizing and analyzing of results of a series of previous studies.

Double-Blind - On Placebos and Self-fulfilling prophecies
Placebo Effect, changes in behavior caused by the belief to have received a drug or any other form of medical treatment. (Placebos work by changing our expectations, we expect medicine to make us feel better and these expectations have for example been found to reduce the actual brain activity linked to pain, so the placebo effect cannot even be claimed to be purely imaginary)

Research Participant Bias certain information about the experiment and their role in the experiment might affect the impact the manipulated condition has on participants because they develop expectiations. Solutions can be to not inform participants what the experiment is about and whether they are in the experimental or in the control group: single-blind experiment

Researcher Bias the risk that researchers will tend to find what they expect to find in an experiment. To avoid both biases it is possible to conduct a double-blind experiment in which neither experimenter nor participants know who is in the experimental and who in the control group and who receives a real drug and who a placebo.

Nonexperimental research methods - Different Strokes

 * 1) The Experimental Method, conducting controlled experiments.
 * 2) The Naturalistic Method, conducting active observation of behavior in its natural setting without any external influence or manipulation. This is first-off purely a descriptive method and further research is needed to establish cause and effect relations. One of the main traps of the naturalistic method is the observer effect, which refers to changes in behavior of the observed caused by an awareness of the presence of the observer. This can be avoided by concealing the observer or making use of hidden recording devices. Furthermore, the observer bias might affect the result, which just as the researcher bias might lead the observer to only record observations which fit and fulfill expectations. Another bias that comes into play when observing animals is the antropomorphic error which refers to the attribution of human thoughts and emotions to animals in order to explain their behavior.
 * 3) Correlational Method, connecting two observations by a correlation. This is done by statistically measuring the correlation coefficient, denominating the grade of correlation between the observations. This is done with the Correlation Coefficient, is a number somewhere between -1,00 and +1,00. Numbers close to 0 indicate a very weak or even non-existent correlation, +1,00 shows a perfectly positive correlation (an increase in one measure coincides with an increase in the other measure), -1,00 a perfectly negative correlation (an increase in one measure indicates a decrease in the other). → Correlation does not demonstrate Causation!
 * 4) The Clinical Method, working with patients in clinics or mental hospitals. Mostly conducting in-depth case studies. Since these studies lack control groups the generalized insights and explanations they can offer are limited.
 * 5) The Survey Method, conducts surveys with a representative sample of people, that is a sample of people which represents the larger population (= a group of animals or people belonging to the same category). Surveys can render quite accurate results but when the sample is biased the result is too, a biased sample is a sample which does not truly reflect the population it is meant to represent. Furthermore, surveys might be affected by the courtesy bias which tends to result in people answering questions in a way which is not truthful but rather socially and politically correct.

=Chapter 2: Brain and Behavior=

Neurons - Building a Bio-Computer
The brain is made up of about 100 Billion neurons and the same number of glials, cells assisting the neurons. Neurons carry input from the senses to the brain and output from the brain to the muscles.

Most neurons have four parts:
 * 1) The dendrites, neuron fibers which receive signals from other neurons
 * 2) The cell-body or Soma, also receives messages from other neurons, but also sends messages itself
 * 3) The Axon, a thin fiber which passes on the messages from the soma
 * 4) The Axon Terminal, the bulb-shaped end of an axon which is connected to other neurons and allows information to flow between them

In and around the neurons are Ions, which may be positively or negatively charged. When a neuron is inactive, also called resting it has more negatively charged ions on its inside and more positively charged ions on the outside. The electrical charge of a resting neuron, called resting potential is about -60 to -70 millivolts at the Axon. The electrical charge of -50 millivolts is the threshold value above which the neuron will "fire", by sending an action potential down the axon to another neuron.

Process inside the axon during an action potential: The axon is pierced by tiny holes all along its length. Normally they are closed by molecules functioning like gates, in the event of an action potential they open and let Na+ sodium ions rush into the axon (before, in the resting potential, the inside of the axon was negatively charged). The first gates open close to the soma and then they continue opening along the axon (just like dominoes, one gate after the opens). After each action potential, K+ potassium ions flow out of the membrane and the neuron briefly returns to its resting potential a status in which it is less inclined to fire.

Some axons are coated over with myelin, the layer has small gaps which help the impulses to move faster, since they don't have to move down the entire axon but can jump from gap to gap: saltatory conduction.

→ while nerve impulses are electrical, communication between neurons is chemical.

Synapse: the space between two neurons. When an action potential reaches the tip of an axon terminal, neurotransmitters are released into the synapctic cleft, these transmitters are chemicals which alter the activity of a neuron. They are received by the receptor sites either on the dendrites or on the soma of the receiving neuron, which are sensitive to neurotransmitters. There are different forms of neurotransmitters, made up of different chemicals, which belong to specific pathways in the brain. Some neurotransmitters excite the receiving neuron, making it more likely to fire and some inhibit it, making it less likely to fire. Neuropeptides regulate subtler brain activity by not carrying messages directly but instead regulating the activity of other neurons.

Neural Networks are interlinked connections between neurons which process information in our brain. When a neuron receives various messages from other neurons, it combines all the messages and checks whether it has received sufficiently more exciting than inhibiting messages and only if that is the case, the neuron fires.

Neuroplasticity describes the capacity of the brain to change in response to experience. → meaning synaptic connections might form but also other connections might weaken and die, this is exactly what happens when changing a habit, the old neural networks triggering the habitual action die while new networks for the new habit are formed.

The Nervous System - Wired for Action
Central Nervous System (CNS) is made up of the brain and the spinal cord. The spinal cord transport messages from the brain to the Peripheral Nervous System, which is a network of nerves (large bundles of axons, most of which outside of the brain and the spinal cord are covered by a layer of neurilemma) carrying messages to and from the spinal cord (31 nerve bundles in total and 12 cranial nerves, running directly from the brain and not through the spinal cord).

A Reflex arc is an automatic response provoked by a stimulus which arises directly in the spinal cord without direction from the brain. Such stimuli are carried to the spinal cord by sensory neurons. Once arrived at the spinal cord, the sensory neuron links up with a connector neuron which has the principal function to connect two neurons with each other. This neuron then activates a motor neuron, connected to muscles and glands. The fibers of the muscles are made up of effector cells capable of triggering a response. Even though the process of reflex occurs within the spinal cord and without intervention of the brain, the spinal cord usually informs the brain afterwards and so conscious responses may follow.

The Peripheral Nervous System itself is divided into two parts
 * 1) The Somatic Nervous System (SNS) which carries messages to an from the sense organs and skeletal muscles
 * 2) The Autonomic Nervous System (ANS) which serves internal organs and glands. Directs mostly automatic processes. The ANS itself is divided into two parts, which are both related to emotion and involuntary actions
 * 3) The Sympathetic System - emergency system which arouses the body for action
 * 4) The Parasympathetic System - quiets the body and keeps vital body functions running

neurogenesis, the way in which the brain produces new brain cells. Daily thousands of neurons grow deep within the brain and then rise to the surface to become a new part of the brain circuit.

Research Methods - Charting the brain's inner realms

 * 1) CT (Computer Tomographic Scanning) an X-Ray Scan of the brain
 * 2) MRI (Magnetic Resonance Imaging) a scanning of the brain of the entire body using a strong magnetic field which then creates a 3D Model of the scanned parts and shows much more details than a CT
 * 3) ESB (Electrical stimulation of the brain), stimulation of the brain with a mild electrical current evoking instant responses by the body
 * 4) EEG (Electroencephalograph) detects electrical activity near the surface of the brain and then records them. It can identify tumors and seizures as well as different states of the brain such as dreaming.
 * 5) PET (Prositron Emission Tomography), measures positrons as they are emitted by glucose (sugar) as it is consumed by the brain. The brain works with sugar from which it gains its energy, thus, areas with more energy are the currently active areas. PETs can produce images of activity both near and below the surface of the brain
 * 6) fMRI (functional MRI) uses the technique of an MRI scan to make brain activity visible

The Cerebral Cortex - My, what a wrinkled brain you have!
The human brain might not be the largest in absolute weight, but with the brain/body ratio of 1/60 it is exceptional in relative size, this ratio is possible due to the corticalization of the brain, meaning the way in which it is folded up and wrinkled so that it fits inside the skull. The brain essentially consists of the cerebral cortex which is divided into two hemispheres and they are again divided into a number of lobes. The cortex largely consists of grey matter (brain tissue made up off cell bodies).

Cerebral Hemispheres, the two hemispheres of the brain are connected by a thick band of axons, the corpus callosum. The two hemispheres underlie the principle of contralteral organization, meaning that the right hemisphere is wired to the left side of the body and the left hemisphere to the right side of the body. Damage to one of the hemispheres might cause spatial neglect, which causes disturbances in perception on one side.

Split Brain, in very extreme cases of epilepsy the corpus callosum can be cut in order to prevent short circuits in the brain. Afterwards two separate brains with their own perception exist within one skull.


 * The Left Hemisphere: usually responsible for all language related abilities, analytical capacities and complex movements. → it processes information sequentially
 * The Right Hemisphere: responsible for all perceptual skills, recognizing faces or patterns as well as expression emotions and recognizing emotions of others. The right side of the brain is not able to produce language in any sophisticated way but if it is damaged people loose the capacity to understand jokes, irony, sarcasm and the like. → it processes information holistically

Even though the hemispheres usually work following the principle of division of labor, it is by no means a strict division and it is always the brain as a whole which is active. However, in very rare and extreme cases, children have been born with only half a brain or one hemisphere has had to be removed at a later point and due to neuroplasticity the remaining hemisphere is able to jump in and fulfill the tasks of the missing half.

Frontal Lobes

Are concerned with higher mental abilities and determine our sense of self. They also direct movement, all those motoric abilities are directed by the primary motoric cortex, that is divided into areas dedicated to directing the movement of certain body parts. The size of the area dedicated to each body part is determined by the importance of the respective body part for motoric actions not by its size. The motor cortex contains a number of mirror neurons which are activated when the body performs a certain act but also when the act is only observed. It might be possible to explain our intuitive understanding of other people's behavior with these neurons and also how we learn behavior, since a specific neural network becomes activate when we observe an action and can subsequently be used to imitate this same action.

The most part of the rest of the frontal lobes is commonly called frontal association area. This association cortex is dedicated to combining and processing information, it receives sensations from primary sensory experiences and then matches them up with memories to create percepctions. They can also contribute to other complex mental processes such as language, damage to the association cortex can lead to aphasia, the inability to use language. If the damage is in Broca's Area it results in difficulties in speaking or writing, also referred to as motoric/expressive aphasia.

The front of the frontal lobes is referred to as prefrontal cortex, it is related to complex behavior and damage to it may result in drastic changes in personality and emotional life → much of what is commonly understood as intelligence is related to activity in the prefrontal lobes

Parietal Lobes

The Parietal Lobes are dedicated to all types of bodily sensation. All these tactile sensation first enter the parietal lobes through the primary somatosensory cortex. Like in the case of the primary motoric cortex area sizes on the primary somatosensory cortex are distributed in relation to the importance of the body part for sensory experience.

The Temporal Lobes

The Temporal Lobes are responsible for all kinds of auditory reception, they are located at each side of the brain. Auditory signals are first received by the primary auditory cortex. The sensations are then passed on to the association cortex in the temporal lobes. One of the association areas on the left temporal lobe is called Wernicke's Area, responsible for language association. If there is damage to this area the result is receptive aphasia, meaning that language can still be expressed but it can no longer be understood. (If damage is to both areas it can even result in a global aphasia with a loss in both receptive and expressive capacity)

The Occipital Lobes

The Occipital Lobes are dedicated to visual input and are located at the back of the brain. The first receiving area of visual sensation is the primary visual cortex. If the association areas of the occipital lobes are damaged a visual agnosia might result, which is the inability to perceive and identify objects. This might also extend to a facial agnosia (prosopagnosia) which is the inability to recognize all faces even familiar faces. A special form of visual agnosia is alexia, the inability to recognize written language.

The Subcortex - At the Core of the Brain Matter
The subcortex is located directly below the cerebral cortex at the very heart of the brain. Damage to it can be fatal.

The Hindbrain

As the spinal cord joins the brain it turns into the brainstem, which in itself is again divided into two parts
 * 1) The Medulla, responsible for reflexes and vital life functions. The pons, a small area on the brainstem connects the Medulla to other brain areas and is responsible for sleep and arousal
 * 2) The Cerebellum, is primarily dedicated to posture and all facets of muscular coordination. It also stores memories related to skills and habits. Damage to the cerebellum results in degrading abilities of any coordinated muscular tasks such as running and can even result in paralyzation.

The Reticular Formation is located inside the brainstem and the medulla and is dedicated to giving priority to sensory input, thus, being responsible for directing attention. It is furthermore involved in both, modulating voluntary movement and involuntary movement such as reflexes. Sensory input are distributed in the Reticular Formation into the Reticular Activating System (RAS), which then stimulates the cortex keeping the person alert and awake.

The Forebrain

The Forebrain is located deep within the brain and contains two of the most essential parts of the brain
 * 1) The Thalamus, is an area through which all sensory input passes on its way to the different brain areas. If it is damaged it can result in a complete impairment of one of several senses
 * 2) The Hippothalamus, is the center for emotions and many basic motives. It is also a connection point for several brain areas and the last station where a lot of behavior is decided upon.

The Limbic System

Is made up of the previously mentioned Thalamus and Hippothalamus, the Amygdala, the Hippocampus and a number of other brain structures. It is dedicated to producing emotion and motivational behavior. The Amygdala is related to emotions such as fear and anger, it is a quick, though rather primitive pathway to the cortex. Disorders in this brain area may prove to be rather disruptive and can explain the nature of phobias and panic where the exact reason of fear is often not clear to the people suffering from them. The Hippocampusis located in the temporal lobes and is responsible for the formation of long-lasting memories as well as navigation through space. Moreover, the limbic system contains both pleasure and punishment areas.

The Endocrine System - My Hormones made me do it
The Endocrine system is a parallel communication system inside our body which also influences behavior. It is made up glands which insert hormones (chemicals that affect both internal activities and visible behavior) into the bloodstream and the lymph system. Hormones are similar to neurotransmitters and influence the activity of cells which have receptor sites for them. The pituitary, a globe shaped section at the base of the brain is responsible for the release of hormones such as the growth hormone or Oxytocin a hormone involved in feelings of happiness, social bonding and trust. It directs many of the other hormonal glands but receives its own directions from the Hippothalamus located above it. The pineal gland releases melatonin regulated depending on variations in light. The thyroid gland regulates the metabolism, the rate with which energy is produced and used up in the body. The adrenal glands, located just above the kidneys, release mainly two hormones that both arouse the body. Epinephrine, linked with fear and Norepinephrine, linked with anger.

=Chapter 3: Human Development=

Nature and Nurture - It takes two to tango
Even though the Nature-Nurture Debate has been raging for a long time it is now commonly assumed that it is neither of the two which solely affects the life of a person. It is an interplay of heritage and enivronment which make a person.

Heredity

Heritage describes how a number of physical and psychological features are passed from parents to their children. Every nucleus of cell contains DNA (Desoxyrbonucleic Acid), it is made up of different organic bases which act as a code for genetic information. Human DNA is organized into 46 chromosomes which contain the instructions for heritage. Only sperm and oval cells contain only 23 chromosomes each, so children inherit 23 chromosomes from each parent. Genes are segments of DNA which affect certain personal traits or characteristics. Genes may be
 * dominant, meaning if this gene is present the feature it contains will be always appear
 * recessive, meaning there needs to be a second recessive gene of the same sort in order for the feature to appear

In reality there are hardly any features controlled by only a single gene, most are polygenic determined by the interplay of various genes. Genes can "switch on or off" at certain stages of development.

The rapidity with which a child will acquire certain capacities such as walking, talking etc. are determined by the readiness to learn, which also implies that certain levels of maturity must be reached before specific capacities can be learned.

Environment

Also called nurture, environment refers to all external influences which affect a person. These influences can already have an effect before birth (such as loud sounds). Congenital problems (or birth defects) can be caused by sickness of the mother or drug or alcohol consumption. All substances which if consumed are capable of disturbing the normal development of the fetus are called Tetarogens. Genetic disorders on the other hand are diseases not inflicted by but inherited from the parents (this includes, anemia, hemophilia and certain forms of mental retardation).

The environment in which a child grows up sets the limits in which the hereditary potential of the child can develop. If it grows up in a deprived environment it might express little of its potential, in an enriched environment it may express it to its fullest. The range between this low and high expression of hereditary potential is called reaction range.

Newborn children tend to differ substantially in their temperament, their inherited personality, including sensitivity, irritability and typical mood. Babies influence their own development in the sense that their behavior influences their parent's behavior towards them and vice versa in a dynamic reciprocal relationship. Inherited temperaments are thus modified by learning.

The Newborn - More than meets the eye
Newborn infants, called neonates are already able to use their senses and in a limited way react to sensory input. They can see, hear, touch, smell and respond to pain. They also have a number of adaptive infant reflexes. The grasping reflex allows them to grasp objects and to hold on to them with remarkable strength. The rooting reflex leads infants to turn their heads when touched and look for the source of the touch. The sucking reflex is responsible for the infant to be ready to feed itself, it can hereby respond to nursing. The Moro reflex comes into play when an infant's position is abruptly changed or it is exposed to a loud noise, the reflex results in a hugging motion.

Maturation is important when it comes to the motor development of a child, while maturation rates vary and children may differ in various months from each other as to when they reach the different stages of motor development the order of the stages tends to be the same for all children. This is also due to two main characteristics of the development of muscular control. It tends to spread cephalocaudal, from head to toe and proximodistal, from the center of the body to the extremities.

Babies are also very prone to imitate mimic, both directly after seeing it as well as remembering and imitating it a day later as early as nine months old. Already as early as 6 months, infants recognize categories of objects differing in color and shape. Children recognize faces from very early on and until they are two prefer familiar faces to unfamiliar ones, at the age of two begins a fascination for the unknown over the known.

Emotional Development

Early emotional development follows a very similar pattern to maturation, the only emotion newborns can express from the moment of their birth on is a general emotion of excitement, all others such as anger, fear or joy have to be learned. One of the most common reactions of a baby to its environment is a smile, which at a later stage turns into a social smile which allows social interaction and a reward for those caring for it.

Social Development - Baby I'm Stuck on you
The very early social development is rooted in emotional attachment and the need for physical contact. contact comfort describes the pleasant and reassuring feeling infants get when touching something soft and warm, especially their mother. A first direct sign for an emotional bond that has developed appears at approximately 8 to 12 months of age. At that time children begin experiencing separation anxiety when they are left alone or with strangers, though this is normal it can turn into a problem when children suffer from a separation anxiety disorder.

The quality of the attachment to their mother is usually tested by observing how children react when their mother returns after a brief absence. securely attached children have a stable and positive emotional bond, they experience distress when their mother leaves and seek to be near her when she returns. Insecure avoidant infants have an unstable emotional bond and turn away from their mother when she returns. Insecure-ambivalent attachment is also rather anxious and children both seek to be near their mother but also angrily refuse contact to her when she returns. The emotional attachment children have early on can have a lasting impact up into adulthood. A baby's affectional need is equally important as its survival need for food or water.

Parental Influences - Life with Mom and Dad
There are three major parental styles of educating children


 * 1) Authoritarian parents, enforce rigid rules and demand strict obedience to these rules
 * 2) Overly permissive parents, give little guidance and do not hold children accountable for their actions
 * 3) Authoritative parents, supply firm and consistent guidance combined with love and affection, they encourage their children to be responsible and to think for themselves

Although maternal influence generally has a greater impact on children, paternal influence also is a unique contribution, fathers have been found to be more likely to play with children and tell them stories while mothers are more likely to respond to physical and emotional needs.

Language Development - Who talks Baby Talk?
Again, both nature and nurture are important for the development of language, it is thus again closely tied to maturation. By about 1 month of age infants tend to use crying to get attention and communicate the various needs they have. At around 6 to 8 weeks, they start cooing, repeating as and os. At about 7 months they start babbling, combining a few consonants with vowels, at first the babbling sounds are the same all over the world, but then they change according to the language the parents speak. From 18 months to 2 years the vocabulary has expanded to over a hundred words, they are soon used in simple one-word sentences and then combined to two-word sentences, a sort of telegraphic-speech.

At the age of two, rightly referred to as the terrible two's, children become prone to tantrums and to behaving a certain way precisely because their parents don't want them to behave that way.

Noam Chomsky has claimed that humans are born with a biological predisposition to language, a hereditary readiness for language learning, which imprints certain grammatical and linguistic patterns in the brain. However, other psychologists advocate a theory which places much more emphasis on learning, especially on the imitation of adults and the mechanism of reward for correct use of language. Long before actually communicating through language, parents establish a sort of communication to their children via a system of signals and especially upheld by taking turns in receiving and sending these signals. The more children interact with their parents, the faster they learn to speak and the faster they acquire learning abilities, this way social relationships enhance communication abilities. From the time that the infants are about 4 months old, parents start to use a kind of baby language, parentese/motherese which does not only use simpler sentences and words but also has a kind of melodious quality to it which appears to be the same across cultures.

Cognitive Development - Think like a child
Jean Piaget's theory of cognitive development: Children think less abstract categories than adults, they tend to generalize and categorize less. Piaget emphasized two central processes for the development of cognitive capacities: Assimilation, applying existing mental patterns to new situations and Accomodation, modifying existing patterns to fit new experiences.

The sensorimotor stage (ages 0-2): Children here tend to focus their learning on coordinating the real world with the sensory information they get. They lack object permanence meaning they cannot retain a mental image of an object once it is out of sight.

The preoperational stage (ages 2-7): In this stage children's thinking has become more symbolical, however, they still lack the ability to transform mental images they retain and their thinking lacks logic and reasoning. During this age children are also unable to put themselves into other people's shows and imagine what they are thinking or feeling, they cannot imagine someone else might not know something that they know. It is therefore sometimes referred to as the egocentric stage.

The concrete operational stage (ages 7-11): The milestone of this developmental stage is the ability to reverse thoughts and realize that if AxB=C, then BxA is also C. In this stage children begin to use concepts of time, space and numbers.

The formal operational space (ages 11 and up): Children begin to use abstract concepts and become more self-reflective. They also start to consider hypothetical propositions and their consequences.They then become able to use inductive and deductive reasoning and to use formal thinking. All further intellect developments are then based on gaining specific knowledge and further insight into specific topics but not on acquiring basic thinking abilities.

Although Piaget's theory is still regarded as valid in many ways today, there is disagreement about specific parts. Especially researchers advocate that children are not going through a stage-like development but rather continuously gain specific knowledge. In addition to that it seems that cognitive development starts earlier than suggested by Piaget. He thought babies under 1 year of age were not able of thinking at all, studies have shown, however, that infants as young as 3 months have concept of the solidity of objects and their continued existence after they are out of sight.

Self-Awareness: Only at an age of about 18 months do children start to recognize their own reflection in a mirror, this development of self-awareness depends on maturation of the nervous system. Recent studies have actually shown that contrary to Piaget's theory children start to show first signs of empathy around the age of 4. This theory on the ability to understand that other people have opinions, views and knowledge different from our own is now commonly referred to as Theory of Mind. Furthermore, many psychologists think that Piaget placed to little emphasis on the importance of sociocultural influences for learning. Such claims include that children acquire knowledge through dialogue with more capable people and the knowledge they acquire depends on these people and the dialogues they sustain with the children. Also children always have to learn certain intellectual values which are specific to their culture. Guidance offered by tutors makes most sense when it takes place in the child's proximal zone of development, so very close but just a little above the mental abilities of the child, this can especially be bolstered, by scaffolding, tailoring guidance especially to children's needs.

Adolescence and Young Adulthood - The Best of Times, The Worst of Times
Puberty is not the same as adolescence, it is a biological not a social state, promoting growth and sexual maturity. emerging adulthood is a trend towards a socially accepted extended period of adolescence.

Moral Development - Growing a Conscience
Lawrence Kohlberg has identified three stages of moral development based on the form of reasoning which is used to derive at moral judgements.


 * 1) The preconventional level, moral judgements are guided by the consequence of actions.
 * 2) The conventional level, moral judgement is based on both, the desire to please others and to follow authority and established rules.
 * 3) The postconventional level, moral judgement is based on self-established moral principles, which are applied generally and universally.

Another study by Carol Gilligan has found that in passing moral judgements men are more concerned with justice as such while women tend to seek solutions guided by the overarching principle of caring for others. Diverging studies have found no such difference between men and women but rather that both genders are concerned with reconciling the principles of justice with those of caring for others.

The Story of a Lifetime - Rocky Road or Garden Path
During life people pass through a number of developmental stages which are all defined by different developmental task, meaning challenges that have to be mastered. Erik Erikson has suggested that everyone faces certain psychosocial dilemmata at each of these stages, which denominates a conflict between personal impulses someone has and the social world surrounding that person.
 * 1) Trust vs. Mistrust (first year of life): The basic attitude of either trust or mistrust in other persons is formed at that time, depending on the kind of care the parents give the child and the bond that results from that care.
 * 2) Autonomy vs. Shame and Doubt (year 1-3): Children gain a sense of autonomy by exerting self-control and endeavoring new things. When their failures are reprimanded they might feel shame or even start to doubt their abilities.
 * 3) Initiative vs. Guilt (years 3-5): Children start to take initiative in trying new things, which can be encouraged if their parent's give them the freedom to do so. If they are however, discouraged or even punished they might feel guilty and even cease to take initiative
 * 4) Industry vs. Inferiority (years 6-12): With entering school for the first time people outside the home and apart from the family become important for the child's development. If the child's behavior is praised it may become a feeling of industry, if instead they are regarded as insufficient a feeling of inferiority might result.
 * 5) Identity vs. Role Confusion (Adolescence): A consistent identity has to built from all the different environment a person moves in, all the different predisposition the person has, expectations and roles it is situated in. If such an identity is not successfully built, role confusion might follow, where people do not exactly know who they are and where they are going.
 * 6) Intimacy vs. Isolation (young Adulthood): intimacy describes the need for people to care for others and share experiences with them as well as receiving back these things through deep friendships and relationships. If people fail to establish these kinds of relationships, they usually experience a feeling of isolation , to be alone and uncared for in the world.
 * 7) Generativity vs. Stagnation (Middle Adulthood): Generativity describes an interest in guiding the next generation which can give people a positive emotional balance. This can be achieved either by caring for one's own children or for others as a teacher or mentor, productive or creative work can have much of the same effect. It essentially includes broadening one's interest so that it includes the welfare of others and society as a whole, failure to do so leads to stagnation on concern for one's own personal interests and can lead to loss of meaning in life.
 * 8) Integrity vs. Despair (Late Adulthood): This stage is essentially marked by reflection. People who have lived fully and responsibly develop a sense of integrity and self-respect. People who view their previous life with regret and remorse may experience feelings of despair and see their life as a series of missed opportunities.

Middle and Later Adulthood
According to Carol Ryff there are six elements which constitute well-being in adulthood
 * 1) Self-acceptance
 * 2) Positive Relations with others
 * 3) Autonomy (Personal Freedom)
 * 4) Environmental mastery
 * 5) A purpose in life
 * 6) Continued personal growth

In old age Warner Schaie found a series of factors which have in influence on keeping people mentally sharp
 * 1) Remaining healthy
 * 2) Living in a favorable environment (stimulating occupation, intact family, above-average income, well educated)
 * 3) Involvement in intellectually stimulating activities (reading, travelling cultural events, etc)
 * 4) Flexible Personality
 * 5) Marriage to an intelligent spouse
 * 6) Maintaining the perceptual processing speed by staying active
 * 7) Satisfaction with accomplishments in life

Furthermore, there are a few characteristics which seem to influence successful aging
 * 1) Optimism, hope and an interest in the future
 * 2) Gratitude and forgiveness, an ability to focus on what is good in life
 * 3) Empathy, the ability to share feelings with others
 * 4) Connection with others, the ability to reach out and to give others social support

Dying and Death - the final frontier
Kübler-Ross has identified 5 basic emotional reactions to impending death
 * 1) Denial and isolation - both of and from any information confirming the proximity of ones own death
 * 2) Anger - both at the fact that one's own death is nearing as at the fact that other people are not yet threatened by death
 * 3) Bargaining - either with oneself or with god, promising different behavior in exchange for more lifetime
 * 4) Depression - upon the realization that death can no longer be held off and that this means a goodbye to friends and family as well as the routines of life
 * 5) Acceptance - coming to terms with death and accepting that fate calmly and peacefully

=Chapter 4: Sensation and Perception=

Sensory Processes - The first steps
Our senses act as transducers, transforming external energy into action potential, each sense here specialized into a certain type of external energy. The raw sensory information that reaches the brain is called sensation, as soon as this information is then organized into meaningful patterns, it is called perception.

Selection, refers to the process in which not all external energy available reaches the brain but only that information deemed most important. Essentially, not all external energy is transduced by the senses, in fact only a small part of the target energy range of each sense is transduced, the energy has to reach a certain minimum, also called the absolute threshold in order for the sense to transduce it. Furthermore, not all types of external energy can be transduced by the senses because humans do not have receptors for all types of energy. Moreover, the senses respond less to unchanging stimuli, if a sense is stimulated by an energy constantly over a certain time it stops to pick up the stimulus. Sensory receptors respond best to changes in sensory input. Through sensory analysis the senses divide the world into important perceptual features and basic stimuli, the focus on perceptual features being an inherent characteristic of the nervous system. What is considered a perceptual feature, however, is also largely identified by experiences early in life.

Once the stimulus is received by the sensory receptors, Sensory Coding takes place, by which the important features of sensory input are transformed into neural messages. In order for two stimuli to be coded differently they have to meet the difference threshold, so be sufficiently different for the difference to be noticeable and hence, codeable.

Phosphenes, are visual sensations caused from mechanical excitation of the retina (pressing hand or fingers on the closed eyelids - now I know what my childhood stars are called!). The sensory receptors in the eye, are also sensitive to pressure, however, only able to code any sensory input into visual sensations, hence, the phosphenes.

Sensory localization, refers to the dependence of the type of sensation that is perceived on the brain are that is activated by the sensory stimulus.

Vision - Catching some rays
The visible spectrum, meaning the range of electromagnetic energies sufficient for the eye to respond to them, consists of a narrow range of wavelengths of electromagnetic radiation, starting at a 'short' wavelength of 400 nanometers.

Hue is the denomination of a set of basic colors that we perceive. The hues correspond to a certain wavelength of light. Hues from rather narrow wavelengths are saturated colors. The brightness of a color we perceive depends roughly on the amplitude of the light waves, greater amplitude leads to brighter and smaller amplitude to less bright colors.

The Structure of the Eye

Images in the eye are focused onto a thin layer of photoreceptor cells in the retina, most focusing is done by a small membrane at the front of the eye, the cornea, which is adjusted by muscles attached to it in a process referred to as accommodation.

The shape of the eye affects its visual abilities, if the eye is too short, farsightedness results, also called hyperopia. Nearsightedness, or myopia is caused when the eyeball is too long. Deformations of the cornea lead to the simultaneous existence of more than one focal point in the eye, called astigmatism. The type of farsightedness typical in old age, is called  presbyopia and is caused by a decreasing flexibility of the lens which makes it harder for it to accommodate.

There are two types of image receptor cells in the eye
 * 1) Cones -responsible colors and sharpness of the image, the fovea in the middle of the retina contains only cones → normal acuity of vision is denominated 20/20 vision. According to trichomatic theory, there are three types of cones, receptive to either red, green or blue, all other colors are combination.
 * 2) Rods - sensitive to light, mostly contained in the areas around the fovea, responsible for peripheral vision, being especially sensitive to movement in the area covered by peripheral vision

The vision produced through the fovea is referred to as central vision. Areas outside the fovea create peripheral vision.

Processing sensory input in the eye: Light comes in to the eye, it hits the retina and then passes through a layer of neurons (ganglion cells, bipolar neurons and the photoreceptors), without stimulating any of them and hits the back of the retina, then it is reflected back, stimulates first the rods and cones (the photoreceptors) than the bipolar neurons and then the ganglions and is thus transformed into a neural signal and passed on to the optic nerve.
 * The Rods and Cones are responsible for a first coding of the visual information (indicating the brightness as well as colors and position of colors. The ganglions and bipolar cells clean this information up
 * The bipolar cells detect edges, accent them and make them sharper
 * The ganglion cells sharpen the color contrast (using a center surround set-up) ganglion cells fire all the time at a moderate rhythm, they can signal presences by either speeding the rhythm up or slowing down → it does so specifically to signal if a certain color hits them (there are red-green cells and blue-yellow cells, red speeds the cell up, green slows it down, blue speeds up and yellow slows down). This firing of either-or messages is explained in the oppponent-process theory according to which a message that is coded in one color of the pair cannot simultaneaously be coded in the other.

There is a blind spot on the retina where the optic nerve leaves the eye and blood vessels enter it. The blind spot usually isn't noticeable because the visual cortex fills in the missing information with information from the surrounding areas.

Color blind people either lack cones or their cones have malfunctions. More commonly this is not a complete color blindness, but rather a milder color weakness. There is, however, a rare form of color blindness which originates in the brain

Hearing - Good Vibrations
Sound is made up of a series of invisible waves of compression (peaks) and rarefaction (valleys). The frequency of sound waves (the number of waves per second) corresponds to the perceived pitch of the sound (meaning either a lower or a higher tone). The amplitude corresponds to the energy contained in the sound (meaning a loud or a soft sound).

The process of hearing

Sound is collected by the outer ear, the Pinna. It is then passed on into the ear canal and then collides with the tympanic membrane (the eardrum). This causes the auditory ossicles, malleus, incus, stapes (hammer, anvil and stirrup) to vibrate. The ossicles connect the eardrum with the cochlea in the inner ear. The stapes is connected to a membrane on the cochlea called the oval window. As the stapes moves, the oval window moves as well and sets fluid inside the cochlea into motion. Inside the cochlea, tiny hair cells that belong to the organ of corti detect this motion. stereocilia on the hair waves brush against the tectorial membrane of the organ of Corti, with the bending of the stereocilia nerve impulses are triggered which then pass on to the brain.

The frequency theory explains how tones of up to 4,000 hertz can reach the brain, as the pitch of each sound is directly represented by a corresponding frequency of sound waves. For higher tones, place theory explains that the different pitches strike at different parts of the cochlea.

Conductive hearing loss describes a damage to one of the connecting membranes of ossicles between inner and outer ear which inhibits the correct passing on of vibration from the outer to the inner ear. Sensorineural hearing loss, describes damage to the inner hair cells of the auditory nerve, this damage can be noise induced. Hearing aids are only helpful when dealing with conductive hearing loss.

Smell and Taste - The Nose knows when the Tongue can't tell
Smell

Smell receptors respond to airborne molecules passing by nerve fibres in the upper nasal passage, the receptor proteins on the fibres are stimulated and pass neural signals on to the brain. According to the lock and key theory of olfaction there are different holes or pockets on the receptors which trigger the chemical reaction leading to an action potential whenever a molecule fits into them and thereby different smells are generated. Odors are, therefore, related to the shape of the molecules which produce them. Furthermore, through the combination of different receptors an even greater variety of smells is possible. In addition to that, the location of the receptor also plays a part in determining which scent is detected. The intensity of the smell, however, is determined by the number of receptors activated.

Dysomia, means a loss of certain receptors which can lead to an incapacity to perceive specific scents. Anosmia then, is the complete loss of the olfactory sense.

Taste

It is commonly assumed that there are at least 4 basic tastes: bitter, sour, salty and sweet. They range in exactly this order from the taste we are most sensitive to, to the one we are least sensitive to. The fifth basic taste is the so called umami, a savory taste related to certain amino acids. Its receptors are especially sensitive to glutamate.

The reason why flavor still seems to varied is because there are other factors taken into account when determining a taste, which are not tasted, such as smell, temperature or texture. From these especially smell is essential in order to taste.

The taste buds are located mainly on the top of the tongue and especially around the edges, nerve impulses to the brain leave the mouth from the taste buds. Sweet and bitter tastes are believed to follow the same lock and key principle as smell, with molecules and accordingly shaped receptors. Sour and salty, however, are triggered by flows of charged atoms into the tips of the taste buds.

The Somesthetic Senses - Flying by the Seat of your Pants
There are three somesthetic senses, which allow for routine movements
 * 1) The Skin Senses, is basically the sense of touch. Skin receptors produce at least five different sensations: light touch, pressure, pain, cold and warmth. The sensitivity of each body part roughly relates to the number of receptors located in that area.
 * 2) The Kinesthetic Senses, receptors in the joints and muscles which help detect body position and movement
 * 3) The Vesitbular Senses, receptors in the inner ear for balance, gravity and acceleration controlled by fluid-filled otolith organs. The semicircular canals are responsible for balance. According to sensory conflict theory, dizziness and nauseas, also known as motion sickness can occur when sensations from eyes and body don't match sensations from the vestibular system.

Pain carried by large nerve fibres constitutes something like the bodies warning system, warning pain is usually a rather short sensation. Pain carried by small nerve fibres on the other hand tends to be a slow, lingering sensation. Especially if the painful stimulus is repeated the bodies reminding system kicks in, reminding the brain that the body has been injured at a specific place.

According to the gate control theory, pain messages from different nerve fibres all have to pass through the same neural gate in the spinal cord before entering the brain. If the gate is then 'closed' by one message, other pain messages cannot get through. This is an explanation why sometimes one painful sensation might cancel others out. Messages from large nerve fibres seem to directly close the gate, so that reminding pain messages can no longer get through. Reminding pain messages seem to pass through the gate without closing it, but then go on to a 'central biasing system' in the brain which in some cases sends signals back to the gate to close it.

Perception - The Second Step
All our experiences are actually perceptual constructions in which the brain matches up raw sensory information with previous experiences and memories to create a perception out of the current sensory input.

This perceptual construction can also lead to misconstruction which can then create illusions, misjudgement of sizes, lengths, positions, motions or directions. They are distorted perceptions of a reality which is actually there. Hallucinations on the other hand are perceptions of objects which aren't really there. To find out whether what one is seeing is a hallucination, reality testing is a help, so for example (since it is mostly visual perceptions which make up hallucinations) try to perceive the object with other senses, so e.g. trying to touch it.

Bottom-up processing: Here the brain starts to construct percepctions from the raw material (the sensations) it receives.

Top-Down processing: Here the brain uses preexisting knowledge to rapidly organize new sensory input into a meaningful whole perception.

The Gestalt Organizing Principles

According to the Gestalt psychologists the simplest organization of sensations into perceptions works through figure ground organization, in which sensations are grouped into figures or objects that stand out on a plainer background. In reversible figures background and visible figure can be switched. The Gestalt psychologists then identified a series of principles which determine whether or not sensation will be grouped in one group or not.
 * 1) Nearness, stimuli which are close to each other are more likely to be seen as a group than those farther apart
 * 2) Similarity, stimuli which are alike in color, shape, size or form tend to be grouped together
 * 3) Continuation or Continuity, perception tends towards simple and continuous forms
 * 4) Closure, the tendency of the brain to see complete shapes with a consistent overall form
 * 5) Contiguity, stimuli which are close to each other in both time and  space tend to be grouped together (a sound and a movement)
 * 6) Common region, stimuli that are found in a common area are grouped together, even if they share characteristics like shape or color with other stimuli outside of this area

Perceptual hypothesis are initial ideas or plans of how a certain sensation could be grouped or could be perceived. The active construction of perceptions is most obvious in ambiguous stimuli which allow for more than one interpretation. Conflicting information can prevent the brain from construction a stable perception, this is for example done by impossible figures. Due to the principle of size constancy the perceived size of an object remains unchanged, even though its image on the retina might change in size. This is uses a top-down plan for constructing the perception, such basic schemata to constructing perceptions even seem to be innate, although others are learned. Analogous to size constancy in shape constancy the perceived form of an object stays the same even though its image might change. in brightness constancy then, the brightness of an object seems to say the same even though lightning conditions change.

Selective Attention - Tuning in and tuning out
Even though the senses themselves already perform a 'selection' of sensations, sensory input is still too much for the brain to handle, so selective attention performs a second filtering. This ability to focus on certain input and ignore others can sometimes even lead to inattentional blindness, the failure to notice a particular stimulus because our attention was focused elsewhere. This has been strikingly proven by the invisible gorilla experiment. The more intense, meaning the brighter, louder or larger a stimulus the more likely it is to be perceived, the same goes for repetitious stimuli. Attention is also attracted by contrast or change in stimuli, especially if these are unexpected.

Depth Perception - What if the world were flat
Depth Perception is the ability to see three-dimensional space and to judge distances accurately. Studies suggest that depth perception is partly learned and partly innate. Our perception of depth is constructed from information supplied by features of the environment and messages from the body which constitute Depth Cues. There are two types of these cues
 * 1) Binocular Depth Cues, require two eyes.
 * 2) Retinal Disparity, the difference of the images which reach the right and left eye. By fusing the two images, 3-D sight becomes possible, also referred to as stereoscopic vision. A striking tale of a woman born without stereoscopic vision but who had the chance to gain it later in life as well as her struggles with it, is told by Oliver Sacks in the narration 'Stereo Sue'
 * 3) Convergence, when judging distances of distant objects, the lines of visions are parallel so that the brain can use information on the position of the eyes to judge the distance correctly.
 * 4) Monocular Depth Cues, can be perceived by just one eye.
 * 5) Accommodation, bending of the lens in order to focus on objects. This can be used to judge distances even with just one eye, however only until a distance of approx. 4 feet.
 * 6) Pictorial Depth Cues, are features found in painting, drawings and photographs that reveal information about depth, space and distance.
 * 7) Linear Perspective, is based on the seeming convergence of parallel lines in the environment, seeing them converge suggests great depth.
 * 8) Relative Size, the distance of objects can be judged by the size they have relative to each other, distant objects are portrayed much smaller than near ones.
 * 9) Height in the picture plane, objects that are placed 'higher' in the picture, meaning closer to the horizon line, are perceived as distant
 * 10) Light and Shadow, clear and coherent patterns of light and shadow can give objects and appearance of depth
 * 11) Overlap, also called interposition, occurs when one object blocks the view of another. The one blocked from sight is then perceived to be more distant
 * 12) Texture gradients, in the distance texture tends to be perceived to be much finer and less pronounced
 * 13) Aerial Perspective, distant objects tend to look washed out and hazed due to fog, dust and smog in the air
 * 14) Relative Motion, or also motion parallax refers to the difference in perceived movement of objects when moving one's own head, near objects seem to move quite a lot, objects farther away move less and very distant objects do not seem to move at all.

Perceptual learning - Believing is seeing
There are a number of factors which affect the accuracy of our perceptions.

Perceptual Expectancies or sets are constructed through past experiences, motives, context or suggestions and prepare the brain to perceive something in a certain way. Through that a perceptual hypothesis is created which makes a certain reaction to a stimulus very likely even though this reaction might be inappropriate.

Motives and Emotions are also important in shaping our perception and determining what our attention is directed to. Negative emotions are believed to narrow the perceptual focus, whereas positive emotions are believed to broaden it.

Perceptual habits, are institutionalized patterns of organization and attention in the brain. Such fixed patterns of perception can be altered through perceptual learning. Perceptual learning also teaches the brain to perceive and interpret new stimuli and to differentiate between stimuli which might at first seem similar.

The Müller-Lyer illusion consists of two horizontal lines one drawn above the other that have exactly the same length, however, one has lines at the end pointing away from it, the other has arrowheads, which makes the latter look shorter than the former.

=Chapter 5: States of Consciousness=

States of Consciousness - the many states of awareness
Consciousness consists of the sensation and perception of external events as well as internal events including thoughts, memories and feelings. Most of our time we spent in a state of waking consciousness, in which we attentively perceive time, places and events as meaningful. However, we usually also experience a variety of altered states of consciousness (ASC). These states are characterized by changes in the patterns and the quality of mental activity. ASCs can be caused by a variety of factors, normal ones like dreaming, disease related ones like brain activity after a stroke, those caused by alcohol or drug consumption, those caused by sensory overload, monotonous stimulation, unusual physical conditions, restricted sensory input and a number of others.

Sleep
Sleep is an innate biological rhythm the absence of which, Sleep deprivation, might result in a decrease in attention and mental capacity but can also cause serious health problems. Hypersomnia, excessive daytime sleepiness might even be experienced after only a few hours of sleep loss. Great sleepiness can also result in microsleeps, brief shifts in brain activity in contrast to the pattern normally recorded during daytime. In extreme cases loss of sleep can result in a so called sleep-deprivation psychosis that is characterized by a loss of contact with reality, hallucinations, delusions and confusion are symptoms of such a psychosis.

According to the repair/resorative theory of sleep, sleep helps keeping the body healthy by lowering body and brain activity as well as metabolism which contributes to conserving energy.

Stages of Sleep - The Nightly Roller Coaster
The brain does not shut down during sleep, sleep simply means a change in brain activity. Such changes in brain activity, in brainwaves, can be recorded by an EEG. Awake the activity shows itself in a pattern of small waves, beta waves. Directly before falling asleep when the brain is relaxed and thoughts drift, the pattern shifts to longer and slower alpha waves. We then fall into sleep moving through four distinct sleep stages.
 * 1) light sleep: Heart rate slows, breathing becomes irregular, muscles relax which may cause a hypnic jerk (a reflex muscle twitch). EEG: small, irregular waves, some alpha waves
 * 2) body temperature drops further, EEG: includes sleep spindles, short bursts of distinctive waves caused by the Thalamus, sleep spindles prevent the body from being awoken by external stimuli and therefore constitute the true boundary of sleep
 * 3) EEG: Delta waves, even slower and larger waves appear
 * 4) deep sleep: the deepest of normal sleeps is commonly reached after about an hour. EEG: almost exclusively delta waves.

Rapid eye movements (REM) during sleep have given the name to this particular phase of sleep, the REM sleep. During REM sleep the EEG shows a pattern of small irregular brainwaves that make it almost look as if the sleeper were awake.

N-REM sleep occurs during stages 1-4 of sleep. It is dream-free 90% of the time and deepest during the fist few stage 4 periods. It increases after physical exertion and helps the body recover. It significantly reduces the overall activity of the brain.

REM sleep is induced by stage 1 periods of sleep later during the night. Daytime stress tends to increase REM phases. REM sleep helps to retain and to sort out memories. Dreams during the REM phase tend to be longer, more vivid and more bizarre than thoughts and images during NREM phases. During REM sleep, brain areas associated with imagery and emotion are also much more active. The heart rate increases, breathing is irregular and men and women equally experience sexual arousal. The body itself becomes extremely still, as if paralyzed.

Sleep Disturbances - The Sleepy Times Blues
Insomnia - includes difficulty in falling asleep, frequent awaking during nighttime, awaking to early, or a combination of these. Worry, stress and excitement can cause temporary insomnia. If the symptoms persist for over three weeks, one can speak of a chronic insomnia.

A nightmare is a bad dream that occurs during the REM phase. Night terrors on the contrary occur during stage 4 of NREM sleep and can lead to panic attacks and hallucinations.

Sleep Apnea stops the breathing for anything between 20 seconds and 2 minutes, until the sleeper awakes and gasps for breath, this cycle may repeat about a hundred times each night. It is suspected that apnea might also be the cause for SIDS (sudden infant death syndrome), or 'crib death'.

Narcolepsy causes victims to fall asleep instantly for anything between a few seconds and half an hour, this can happen while standing, talking or even driving. It is especially triggered by emotional excitement, most of all laughter. Many of these also suffer cataplexy, a sudden and total paralysis of the body. This is related to the fact that narcoleptics fall directly into REM sleep, which brings paralysis with it.

Dreams - A Separate Reality?
REM rebound, when people are prevented from entering REM sleep over a longer time they spend more time dreaming afterwards, to 'catch up' the lost dreams. However, this is not a particular characteristics of REM sleep, missing any of the sleep stages causes a rebound for this stage.

According to Freud's Psychodynamic Dream Theory, dreams reflect the unconscious desires and wishes of people. In order to understand the hidden latent content of dreams the visible manifest content has to be interpreted. The Activation-Synthesis Hpothesis, on the other hand, assumes that during dreams several lower brain parts are activated and send random signals to the brain from which the brain then tries to make sense and synthesizes them into a dream. Through that while dreams are not assumed to have any hidden meaning they do reflect the mental and emotional concerns of a person because dreams are essentially constructed from past experiences. Starting from the observation that many brain areas that are active in the waking state remain active while dreaming, Neurocognitive Dream Theory assumes that dreams are just reflection and continuation of normal daytime thoughts and concerns. The last hypothesis is currently the one most commonly assumed to hold.

Meditation and Sensory Deprivation
Meditation is a mental exercise to alter consciousness, it focuses attention and interrupts the usual flow of thoughts. Brain scans show that during meditation there is a change of activity in the frontal lobes. There are two different kinds of meditation approaches. Concentrative meditation attention is focused on a single object, thought or action, in mindfulness meditation is opening consciousness to adopt a wide and nonjudgemental attitude towards the world. Meditation can have both physical and mental benefits, the former include a lower heart rate, blood pressure and muscle tension. On the psychological side it reduces stress and fosters skills such as clarity and concentration.

Sensory Deprivation describes any major reduction in the amount or variety of sensory stimulation. While long periods of deprivation can be very harmful, short periods spent e.g. in small flotation tanks have relaxing effects similar to those of meditation. Such an REST Restricted Environmental Stimulation Therapy can induce states of deep relaxation, make people more susceptible to suggestions and more open to changing habits. It is also used as a therapy to treat drug or alcohol addiction as well as stress.

Drug Altered Consciousness - The High and Low of it
Psychoactive drugs are all substances capable of altering attention, judgement, memory, time sense, self-control, emotion or perception by directly influencing brain activity. Stimulants (uppers) increase activity in the body and in the nervous system and depressants (lowers) do exactly the opposite. Typically drugs do that by imitating neurotransmitters or by altering their effects, causing more or less neurotransmitters to be released. Nearly all addictive drugs stimulate the brains reward circuit, especially the nucleus accumbens which releases dopamine and thus produce intensified feelings of pleasure.

There are two different kinds of addictions to drugs that people can develop
 * 1) Physical dependence, in that the body depends on the drug to function. This is most typical for drugs which cause withdrawal symptoms when stopping. An addiction is also often accompanied by heightened durg tolerance that makes it necessary for users to take larger and larger doses to experience the same effect.
 * 2) Psychological dependence, in that the drug becomes necessary to maintain the comfort and well-being of the user.

Polydrug abuse, the consumption of various drugs at the same time is a frequent cause for death, since the drugs mutually enforce the effects they have and risks increase

Uppers
Amphetamines, synthetic drugs, legitimate use: esp. Ritalin and Adderall treatment of Attention Deficit/Hyperactivity Disorder ADHD. Abuse: study drug. Metamphetamines are stronger amphetamines, they include e.g. crystal and meth. Side-effects can range from nauseas to psychosis that can result in paranoia and violent behavior. Amphetamines act by speeding up the use of body resources making people feel much more energetic for a short period but also essentially burning up their energy resources.

Cocaine is extracted from the leaves of the Coca plant and acts by stimulating the central nervous system. Even though Cocaine and amphetamines have the same effect their main difference is the duration of the effect, while amphetamines can last several hours, Cocaine gives a short rush between a few minutes and half an hour. Abuse: Cocaine poses a high risk for addiction almost to be likened to heroin. It provokes the release of dopamine (causing a rush of pleasure) and noradrenalin (arousing the brain), this combination is so powerful that it can even turn casual users into addicts and lead to strokes or heart attacks. Withdrawal of Cocaine has no directly visible physical effects but leads to severe depression.

MDMA/ecstasy, is similar to amphetamines, but additionally leads to higher release of serotonin making people feel closer to others. It has several damaging side-effects from jaw-clenching to sometimes fatally elevated body temperature and arrhythmic heartbeats.

Caffeine acts by blocking chemicals in the brain which normally inhibit or slow nerve activity. Caffeine when consumed in relatively small doses can already cause anxiety, when consumed compulsively it can cause chills, racing heart, loss of appetite etc.

Nicotine is most of all found in tobacco. It is highly addictive and its withdrawal symptoms can be likened to those of heroin.

Downers
Barbiturates, are sedative drugs that depress brain activity. Medically they are used to calm patients or to induce sleep. In small doses their effect is similar to alcohol, in higher doses they can cause hallucinations and loss of consciousness which can lead to death. They cause actual physical dependence as well as psychological and withdrawal can cause depression and even suicide.

GHB, is a central nervous system depressant that relaxes the body. It is similar to alcohol leading to a desire to socialize and lowering inhibition. Overdoses can lead to nauseas and loss of muscle controls. A fatal dose is only three times the amount usually taken by users. It is highly addictive drug with withdrawal symptoms from anxiety to hallucinations.

Tranquilizers lower anxiety and reduce tension. In small doses they can cause shakiness and confusion and in larger doses over a longer time span they can be addictive. Rohypnol which has similar effects to Valium, however, is 10 times more potent and far cheaper is frequently put in drinks to make victims fall unconscious and then abuse them.

Alcohol is actually ethyl alcohol from distilled liquor. While it is often believed to work as a stimulant it actually is a depressant, lowering inhibition and thus leading to euphoria and relaxation. alcohol myopia is the dulling of perceptions and thinking of people when they are drunk, an effect that commonly leads to extreme behavior in the drunk. Heavy abuse of alcohol severely damages the body and the inner organs. Withdrawal first starts with detoxification, sobering up and cutting of the supply. In this phase withdrawal provokes all the common symptoms of drug withdrawal and is extremely unpleasant.

Hallucinogens
Hallucinogens generally affect neurotransmitters in the brain.

PCP and LSD, LSD is one of the most well known hallucinogens producing hallucinations and psychotic-like disturbances even when taken in small amounts. Other common hallucinogens are mescaline and psilocybin (magic mushrooms).

Marijuana and Hashish are derived from the hemp plant. Tetrahydrocannabinol (THC) is the main chemical active in marijuana, it causes relatively subtle effects compared to other drugs however compulsive use may lead to paranoia and hallucinations. THC accumulates in the fatty tissues in the brain so even after a week without smoking the body is never fully free of THC. Recent studies have even found that THC creates physical dependence although the far greater danger is the psychological dependence.

=Chapter 6: Conditioning and Learning=

What is Learning
Learning is defined as a relatively permanent change in behavior due to experience. There are generally two types of learning
 * 1) Associative Learning, where a simple association between various stimuli and responses is found. Associative learning is especially fostered by reinforcement, any event that increases the probability of a response occurring again. Responses here refer to any kind of identifiable behavior, externally observable as well as internal.. Antecedents are all events which precede a response, consequences are all events which follow from the response.
 * 2) Classical Conditioning focuses on the the antecedents of responses. It links an antecedent stimulus that does not elicit a response with another stimulus that does. Learning has taken place when the stimulus formerly not linked to the response evokes that same response on its own.
 * 3) Operant Conditioning focuses on the consequences of responses. It links certain responses with two types of consequences, either reinforcement (positive) or punishment (negative). Depending on the consequence a certain behavior will be learned (or similarly a certain behavior might be learned to be avoided)
 * 4) Cognitive Learning, where understanding, knowledge, anticipation or similar processes make use of higher mental processes

Classical Conditioning - Does Pavlov ring a bell?
Classical conditioning is also sometimes referred to as Pavlovian conditioning or responsive conditioning.

Pavlov conducted his experiments by linking an unconditioned stimulus (US), a stimulus that is innately capable of eliciting a response, that triggers an unconditioned response (UR), a response that does not have to be learned and that constituted a reflex (a dependable, inborn stimulus-response connection) to a neutral stimulus (NS), a stimulus that at the start does not trigger any specific response at all. After conditioning this latter stimulus will turn into a conditioned stimulus (CS) which from then on evokes a conditioned response (CR), a learned response linked to the stimulus through conditioning.

Principles of Classical Conditioning
Training a subject to respond with a CR to a CS is called acquisition. During acquisition the CR must be reinforced, such a respondent reinforcement refers to the pairing of an NS with a US in order to evoke the desired response. Once that response is sufficiently learned, the next step brings high order conditioning, in which the now learned CS can be used like a US: This would mean substitutin the original US with the CS and then bringing in a new NS which will eventually turn into a CS linked with the initial UR. So in high-order conditioning the stimulus which actually constituted the basis of the initial response is substituted by the stimulus the subject learned to associate with the response.

Informational theory believes that the processes brought forward under classical conditioning are no higher cognitive processes, but simply a change of expectancies due to association between stimuli and responds. As the CS reliable precedes the US, the expectancy is that it always will and thus the CR is simply a preparation for the US.

Extinction describes how the association that has been learned during the conditioning can be forgotten again. By repeating the CS without letting the US follow for a couple of times will lead to an extinction of the association between CS and CR and the response will no longer follow the CS. This extinction may take quite some time and it is likely that for a few days, at the start of every session the CS will at first evoke the CR again, this is called spontaneous recovery.

After conditioning stimuli that were never used in the conditioning but that are similar to the CS might also elicit the CR, this is called generalization. The contrary process to this is discrimination in which the subject learns to distinguish between various stimuli and respond differently to each.

Classical Conditioning in humans - an emotional topic
It is also possible to associate more complex and emotional responses to new stimuli through learning.

Phobias, fears that persist even if there is no real danger are commonly assumed to begin as Conditioned Emotional Responses (CERs), meaning a learned emotional reaction to a previously neutral stimulus. Through high-order conditioning and stimulus generalization this CER can then even spread further and to other stimuli that were not initially connected to the phobia at all. During such a CER the amygdala in the limbic system becomes active evoking feelings of fear. Cognitive learning has very little effect on these lower brain areas which explains why rational explanations and theoretical information on the combating of such phobias is usually of little help to actually overcome them. They do, however, yield to a process called desensitization, an exposure to the feared object or situation while the person remains calm and relaxed.

Vicarious classical conditioning (or secondhand conditioning) is a form of indirect conditioning that takes place when people learn to respond emotionally to a stimulus by observing other people's responses to it.

Operant Conditioning - Can pigeons play Ping-Pong?
This form of conditioning also called instrumental learning forms an association between a response and a consequence and is based on the principle that behavior which is reinforced tends to be repeated. This is also described by the law of effect: The probability of a response is altered by the effect it has.

In contrast to the passive learning in classical conditioning, operant conditioning is active, focusing on the learning of voluntary responses. It is important to distinguish between rewards and reinforcers. Rewards might not be the same for everyone and suggests a rather narrow spectrum of consequences, however operant reinforcers are all the consequences of a behavior which increase its probability of occurring again.

It is also fundamentally based on expectancies and information, in that operant conditioning teaches the subject to expect that a certain action will evoke a certain consequence at a certain time. It is most successful when the reinforcement is response contingent, meaning it only follows the desired response and when it follows immediately on the response, the longer the delay the smaller the learning effect.

response chaining is the maintenance of a long chain of responses by a single reinforcer. Such chains can be constructed by shaping, a process which gradually arranges a number of responses into a desired pattern. This happens by reinforcing successive approximations, behaviors which come closer and closer to the actually desired response.

Operant extinction, the fading away of conditioned responses, takes place when the response is no longer reinforced. This does not happen at once but gradually. Just as in classical conditioning, spontaneous recovery is likely to happen for some time after initial extinction.

While positive reinforcement refers to adding something positive in order to reinforce behavior, negative reinforcement refers to taking away something negative in order to reinforce behavior. Both types encourage the desired response to be repeated.

Punishment, on the other hand, refers to discouraging a certain behavior by following the response with an aversive consequence, adding something unpleasant. Another consequence that makes the repetition of a certain behavior less likely is the removal of something positive, e.g. taking away a privilege, referred to as response cost.

Experiments have been made, both with humans and with rats, that gave them a possibility to stimulate the pleasure centers or the reward circuit in their own brain. Rats would turn to stimulate their own brain over a thousand times per hour, neglecting even food and water. Further reports on these experiments can be found in the article The Neuroscience of Pleasure.

Operant Reinforcers - What's your pleasure?
Primary Reinforcers are natural, non-learned and deeply rooted in human behavior. They either produce comfort, end discomfort or satisfy a concrete physical need.

Secondary Reinforcers are learned reinforcers and can range from money, over praise to good grades. Often secondary reinforcers are learned because they are at first given together with primary reinforcers until they are independently recognized. This can also happen quite directly when a secondary reinforcer can be exchanged for a primary reinforcer, such as money does not have a value as such but can be exchanged for goods or food. Such tangible secondary reinforcers like money are also called token reinforcers. The advantage of tokens is, that they do not lose value as quickly as primary reinforcers (which lose value as soon as the underlying need such as hunger or thirst is satisfied), but can be kept to be exchanged for a primary reinforcer at a later point.

Feedback is an information about the effect a response had knowledge of results and is especially important in cognitive learning. Feedback is most helpful when it is frequent, immediate and detailed.

Partial Reinforcement - Las Vegas a Human Skinner Box?
While at the beginning of a learning process it makes sense to reinforce every occurrence of a desired behavior by continuous reinforcement, it later becomes more advisable to reward only some instances of the right behavior via partial reinforcement. Behaviors learned by partial reinforcement are highly resistible to extinction (Partial Reinforcement Effect).

There are four basic schedules of partial reinforcement, plans that determine which responses will be reinforced.
 * 1) Fixed Ratios determine an invariable set or number of repetitions of the desired behavior which have to be completed before a reinforcement is given. Such schedules produce very high response rates.
 * 2) Variable Ratios determine only the average number of responses that have to be delivered before a reinforcement is given, so the concrete number necessary might always be a different one. They also produce very high response rates. However, because reinforcement is less predictable than in fixed ratios, variable ratios are much more resistant to extinction.
 * 3) Fixed Intervals determine a fixed amount of time that has to pass before a behavior is reinforced again. All behavior before that time has passed, even if desired, is not reinforced. Such schedules produce a moderate response rate.
 * 4) Variable Intervals determine an average time that has to pass before the next reinforcement. They produce very slow and steady response rate and are extremely resistant to extinction.

Stimulus Control - Red Light, Green Light
Stimuli control describes how stimuli that consistently precede a rewarded response tend to influence when and where the response is likely to occur. Just as in classical conditioning, generalization and discrimination play a role in operant conditioning. Generalization here describes the tendency to respond to stimuli which are similar to the one that preceded operant reinforcement. Discrimination describes how behavior is adapted so as to match different rewarding and nonrewarding stimuli.

Punishment - Putting the brakes on behavior
Punishers are all consequence that decrease the probability of a behavior to be repeated. The effect a punishment has, depends on its timing, consistency and intensity. It should be given immediately after the behavior that is to be punished occurred and it should be consistent in being given each time that behavior occurred. Highly intense punishment, evoking extremly unpleasant feelings are highly successful in preventing undesired behavior from being repeated, mild punishment tends to only temporarily suppress the behavior.

Since punishment is aversive (unpleasant), people and situations associated with punishment tend to be feared and disliked by the subject. Furthermore, punishment encourages both escape learning, learning to make a response to end an unpleasant stimulus and avoidance learning, learning to make a response in order to postpone or prevent discomfort. When avoidance is learned it is very hard to extinguish the learned behavioral pattern. Punishment can also greatly increase aggression in the punished.

Cognitive Learning - Beyond Conditioning
Cognitive learning generally refers to all learning related to information-rich higher cognitive processes. It extends to thinking, memory, problem solving and language.

There are different ways in which such cognitive learning might take place. Cognitive maps are internal representation of areas, topics or any other kind of interconnected knowledge. Latent learning, or hidden learning, is any learning that occurs without obvious reinforcement and remains hidden until reinforcement is provided. In Discovery Learning, knowledge is acquired by insight and understanding and not by rote (mechanical repitition and memorization).

Modeling - Do as I do, not as I say
Observational Learning encompasses both, watching and imitating the behavior of others and learning from the consequences of other people's behavior. By observing a model, essentially three things can be learned
 * 1) A new response
 * 2) To use or not to use an already learned response
 * 3) A general rule that applies to various situations

For observational learning to take place the observer has to pay attention to the model and has to remember its actions, the observer then has to be able to reproduce the observed behavior. If the model is successful with the behavior or rewarded for it, the observer is more likely to try behaving the same way. Behavior is more likely to be imitated and enacted then statements about behavior tend to be followed.

=Chapter 7: Memory=

Stages of Memory - Do you have a Memory like a Steel Trap? Or a Sieve?
Memory is an active system that receives, stores, organizes, alters and retrieves information. There are three memory systems which all proceed incoming information through the same three steps.


 * 1) Encoding, transforms incoming information into a useable format
 * 2) Storing, stores this transformed information in the memory system
 * 3) Retrieving, takes this information out of storage again when it is needed

Memory Systems

Information is first encoded in the sensory system which stores an exact copy of the perceived for a few seconds or less. Iconic memories are brief flashes of images of visual information and can usually be stored for about half a second. Echoic memories are brief flashes of activity in the auditory system and can be stored for about 2 seconds. When a specific part of a sensory input is selectively attendedto it will most likely pass from the sensory memory system into the short-term memory system

The short-term memory system stores small amounts of information which we are conscious about for about 12 seconds. They can be encoded as images but more common is that they are encoded phonetically, as words or sounds. Unless information is rehearsed it is not passed on to the long-term memory system and will be forgotten again. The short-term memory system is highly sensitive to interruption or interference, it can only with great difficulty handle more than one task at the same time. Short-term memory when combined with other mental processes can also act as working memory, briefly holding information while we are thinking or solving a problem.

Information that is important or meaningful is retrieved from short-term memory and stored in the long-term memory system. This holds all the actual knowledge a person has and has an unlimited storage capacity. Logn-term memories are typically encoded as meanings. We are most likely to remember information that is personally important or meaningful to us.

Short-Term Memory - Do you know the Magic Number?
Short-term memory is on average restricted to the storage of seven information bits, a bit being a single meaningful piece of information (such as a digit or a word). Information chunks are bits of information that are grouped in larger units. With chunking information is recoded into information that is already stored in the long-term memory system and thus it becomes easier to remember. The short-term memory system can not hold strictly 7 bits of information but it might also be 7 chunks of information, so simply seven meaningful units independent from the size of these units.

In order to store information longer in the short-term memory system the information can be silently repeated in a process called maintenance rehearsal. This can also be used to permanently store information in the long-term memory system, this is then called rote learning a very bad strategy to actually learn something.

Long-Term Memory - A Blast from the Past
Through elaborative processing all our memories are constantly updated, changed, lost or revised. This processing makes us extremely vulnerable to source confusion, the failure to correctly attribute a memory we have to the source it is from.

Information in the long-term memory system is organized in memory structures, patterns of association between different pieces of information. It is believed that our brain works as a network model linking information according to meaning in large networks of associations. Redintegration is a process that spreads through the memory network. One piece of recollection can trigger a whole chain after which a complete past experience might be discovered.

More elaborative processing creates more elaborate memory networks and thus provides a higher number of retrieval cues which can trigger redintegration.

Long-term memories fall into at least two broad categories


 * 1) Procedural Memory, or skill memory. It includes both basic conditioned reflexes as well as more complex learned actions. Most likely lower brain parts as the cerebellum or the basal ganglia are involved in storing these kinds of memories which can only be retrieved in the form of actions.
 * 2) Declarative Memory stores specific factual information such as names, number, places, people etc and can be expressed in words or in symbols. It can further be divided into
 * 3) Semantic Memory is a collection of impersonal basic facts we know about the world (such as the names of the seasons or the days of the week). Its retrieval is never related to the context in which the information was first learned.
 * 4) Episodic Memory is a collection of personal experiences. It does not merely store facts but actually allows to go back in time and re-lieve an event. Episodic memories are always related to a context, because they basically are the memory of a context. They are more easily forgotten, or some part of them is formed into a semantic memory while the rest of the context is then forgotten.

Measuring Memory - The Answer is on the Tip of my Tongue
Partial Memories are very common, this can lead to the well-known feeling to have something on the tip of one's tongue, the TOT-Effect, the knowledge that an information is there but it is not quite retrievable. The feeling of knowing something is also a result of partial memories, it means knowing that an information is there but no knowing the information itself. Another example is the phenomenon of Deja Vu, the feeling of already having experienced a situation before while actually experiencing it for the first time.

A recall is a direct retrieval of a piece of information. Such tests often require quite verbatim (word for word) retrievals of information. When remembering a long series of words, most errors tend to occur related to middle words, due to the serial position effect, while the first words entered empty slots in short-term memory, the last words are still fresh. The middle words, however, have none of these advantages. Recognition is the identification of previously learned pieces of information. Distractors are false items included with the item that is supposed to be recognized. Recognition is difficult when the distractors are very closely resembling to the actual item, but also when one item stands out a lot, this can lead to a false positive, a false sense of recognition.

Relearning is the most sensitive measure for memory, letting someone learn something once and then later when it is consciously forgotten, relearn the same information, it is measured with a savings score (the amount of time saved on the already learned information.

Explicit Memories are past experiences that are consciously brought to mind, recall and recognition rely on explicit memory. Implicit memories, however, lies outside the range of awareness. Priming is a process that refers to giving hints to someone tested which then make it easier to access hidden information outside the access of his consciousness.

Forgetting
Most forgetting of long-term memories tends to occur directly after memorization. When drafting a curve of forgetting it becomes obvious that forgetting is fairly rapid at first and then enters in a slow decline. However, meaningful information subjected to strong learning often becomes nearly permanent. Most forgetting is due to encoding failures, when a memory is not correctly formed in the first place and/or details are omitted or not encoded correctly.

Another theory holds that we constantly lose memory traces due to storage failure as part of memory decay. This seems to apply especially to sensory memory and short-term memory. Disuse may be a partial explanation for forgetting long-term memories, through infrequent retrieval long-term memory can sometimes fade so thoroughly that it may not be retrieved anymore.

The third possibility is retrieval failure. One reason why we might fail to access already stored memory is that retrieval cues might be missing or we get the wrong retrieval cues at the moment when we try to access the information. According to state-dependent learning, information is also most accurately remembered when one is in the same state at retrieving as at learning. This extends to conscious states as well as emotional states. Interference is the tendency of new information to impair our ability to retrieve older memories. It is not clear whether new memories actually alter older memories or if they just make them harder to retrieve. Retroactive interference is the denomination for such an inhibition of retrieval through new memories. Proactive Interference, on the contrary is when old learning inhibits the retrieval of new learning. The greater the similarity between the two types of information the more interference in likely to occur.

Related to skills, however, this is exactly the opposite. Positive transfer takes place when the mastery of one skill facilitates the learning of another. In negative transfer the opposite occurs and previously learned skills inhibit the mastery of new skills.

Repression or motivated forgetting is the tendency to remember positive experiences and banish negative ones. This has to be differentiated from suppression, an active and conscious effort to put something out of one's mind.

Memory and the Brain - Some Shocking Findings
Retrograde amnesiais the inability to recall events which preceded a damage to the brain. It takes time to form a lasting memory, a process called consolidation. The Hippocampus is the part of the brain most important for consolidation, it acts like a converting station between short-term and long-term memories, partly by growing new neurons and partly by forming new connections with the brain. Anterograde amnesia is the loss of any memory after the accident, it can occur due to damage to the hippocampus (like patient H.M.).

A flashbulb memory is a very vivid image frozen in memory of an emotionally significant either personal or public event. During such situations the limbic system is activated, something which seems to intensify consolidation. While flashbulb memories have proven to be frequently inaccurate, what sets them apart is that people tend to place great confidence in them.

Brain scans have shown that long-term episodic memory tends to be stored in the frontal cortex, while long-term semantic memory is stored in the back of the cortex. Long-term procedural (skill) memory is stored in the cerebellum and the basal ganglia.

Exceptional Memory - Wizards of Recall
To solve certain mental tasks, many people form mental images, this has strikingly been shown in a study where people were tasked with remembering a map and then moving a dot on that map. The time to mentally move the dot from one landmark of the map to another corresponded exactly to the distance between the landmarks on the actual map.

Eidetic imagery is related to what is commonly referred to as photographic memory, it describes images a person retains for over 30 seconds and is able to scan and inspect. Eidetic memory is more pronounced in childhood and declines in adulthood.

=Chapter 8: Cognition, Language and Creativity=

What is Thinking?
Cognition generally refers to all variants of mentally processing information. Very basically we can say that thinking is a kind of internal representation of a problem or a situation, which makes it possible to plan ahead. Thinking has three basic units, images, concepts and language.

Mental Imagery - Does a Frog Have Lips?
Mental images are much more than just visual depictions, for most people they also include information on movement, sound, taste and smell. Synethesia is a very pronounced form of mental imagery, allowing people to associate sounds with colors or shapes with tastes.

When creating mental images, the brain works in reverse as compared to normal visual perception. First, stored memories are accessed and then these are passed on to the primary visual cortex which creates an image based on these memories. Stored images can help applying past experiences to a current problem, whereas, created images make it possible to imagine new and creative approaches. Kinesthetic images (or motor images) are created from muscular sensations and help thinking about movement and actions.

Concepts - I'm Positive it's a Watchamacallit
Concepts are ideas representing categories of objects or situations. Concept Formation is the classification of information in meaningful categories. It is mostly based on experiencing positive and negative instances, encountering objects or events which belong and those that don't belong in the established category. Deciding whether they belong to the category or not is based on the guideline given by a conceptual rule. In addition to that, prototypes, ideal examples are used to identify a concept.

Types of Concepts
 * 1) Conjunctive Concepts, require objects or events to possess two or more features in order to fall into this category
 * 2) Relational Concepts, require a relation of an object or event to another or a relation between features
 * 3) Disjunctive Concepts, require objects or events to have one of several possible features, the features have an exclusive 'either-or' relation.

The denotative meaning of a concept is its exact definition, the connotative meaning is its personal or emotional meaning.

Language - Say what?
Words are two-directional tools, on the one hand they encode the world into symbols that can be handled by thinking, on the other hand, they also influence the way we think about certain things. The study of meaning in words and language is called semantics.

Phonemes, basic speech sounds, are the basis for building words. Morphemes are the collection of these into meaningful units such as syllables or words. Grammar is a set of rules to group sounds into words and words into sentences, syntax refers to word order.

Noam Chomsky has focused on the unspoken rules humans use to to change core ideas into various different sentences. He believes that we create sentences by applying transformation rules to innate core universal grammar patterns.

American Sign Language (ASL) is not a simple code or mime, it is a language like any spoken language. It has a spatial syntax, grammar and semantics but still inherently follows the similar universal language patterns.

Problem Solving - Getting an Answer in Sight
Heuristic is a strategy for identifying and evaluating problem solutions, it basically is a rule of thumb that helps to reduce the number of alternatives someone has to consider to solve a problem.

Some problems are solved by insights a rapid understanding of the solution based on a reorganization of the problem. Insight is based, first, on selective encoding, encoding only the information that is truly relevant to the solution of the problem. Second, selective combination, bringing together seemingly unrelated pieces of information. Finally, selective comparison, comparing the current problem with prior already solved problems.

One of the most common hindrances to successful problem-solving is fixation, becoming too focused on one strategy of solution and thus being blind to alternatives. Functional fixedness describes a blindness towards possible new uses of already known objects. Further obstacles to problem-solving include
 * 1) Emotional barriers, being afraid of making a mistake or of looking stupid if the solution doesn't work
 * 2) Cultural barriers, learned values which judge creativity and playfulness negatively but rules and reason very highly
 * 3) Learned barriers, any kind of convention about uses or possibilities
 * 4) Perceptual barriers, habits which make it hard to identify the important features of a problem

Once someone has gained expertise in an area, a lot of information related to the problem is automatically processed by relating it to previous experiences, this way space in short-term memory is freed which can than be used for the actual problem-solving.

Creative Thinking - Down Roads less Travelled
Thinking can either be inductive, going from specific facts and information to general rules and principles, or deductive, going from general rules and principles to specific situations. It can also proceed logically, by proceeding from given information to new conclusions on the basis of existing rules, or illogically by being intuitive or associative.

There are three factors with which one can rate the creativity of suggestions. Fluency, the total number of suggestions made. Flexibility, the number of times a shift from one possible suggestion to the other is made. Originality refers to how novel and unusual the suggestions are (in order to qualify as a truly creative solution, however, the suggestion must also be fit to actually solve the problem at hand). Such behavior in problem-solving leads to divergent thinking, finding solutions starting from the problem itself without an established proceeding to solve it. Convergent thinking, on the other hand, is thinking in order to find the one correct answer to the problem at hand (this is the way most problem-solving is taught at school).

Intuition - Mental Shortcut or Dangerous Detour?
Intuition is defined as quick impulsive thought. It might be helpful to pass quick and useful judgement, but it may also fall prey to a number of flaws.
 * 1) Representativeness heuristic, there is a tendency to value a choice higher when it appears to be representative of knowledge we already have.
 * 2) Ignorance of the base rate of probability for a certain event to take place.
 * 3) Framing, the way in which a problem is formulated or a question is asked influences our judgement. The best or most impartial decision is reached when the problem is stated in broad terms, the narrower it is framed the more it leads to only one possible answer, discarding other options
 * 4) Emotions, emotions also tend to cloud our judgement and influence the intuitive answer we give

=Chapter 9: Intelligence=

Defining Intelligence
It is very hard to define intelligence, especially because it is not directly observable. In general intelligence is said to be the global capacity to act purposefully, to think rationally and to deal effectively with the environment. It consists of a small set of mental abilities, called the g-factor. These span the areas of reasoning, problem solving, knowledge, memory and successful adaptation to the environment. But beyond this very basic definition there is little agreement and a lot of psychologists simply use an operational definition by referring to the methods they use to measure it.

Intelligence can be differentiated from aptitude, which is the capacity for learning certain abilities. They can be tested in a variety of tests, testing either narrowly or broadly. Special aptitude tests test capacities in only one particular area, multiple aptitude tests measure two or more types of abilities and general intelligence tests are the broadest in scope, measuring a wide spectre of mental abilities.

In order for an intelligence test to be accepted as an actual test of intelligence, it has to be deemed reliable and valid. Reliability means that the results have to be consistent and highly correlated, in addition to that, validity proscribes that a test must also make sure to really measure what it claims to measure.

Furthermore, a test needs to be objective, it has to yield the same results independent from the person who corrects the test. It also has to be standardized, using the same format with all participants and relating results to the 'norm', the average of the respective group tested.

Testing Intelligence - The IQ and You
One of the most widely used IQ tests is the Stanford-Binet Test, it tests five different areas of mental abilities, testing each with verbal as well as nonverbal questions. The abilities tested are fluid reasoning, knowledge, quantitative reasoning, Visual-spatial processing, working memory.

The Wechsler Test is another popular intelligence test. It also yields an overall score and gives separate scores for performance intelligence (nonverbal) and verbal intelligence (language or symbol-oriented).

Earlier, the Intelligence Quotient was calculated by dividing the mental age of the test subject (judged from the questions the person was able to answer) by its chronological age (the real age in years) and then multiplying the result by 100. Today this method is no longer used, instead IQ deviations are used, by referencing the result of a person in the test to a table indicating the person's relative standing.

During the first years of childhood the IQ is not very stable, only starting from middle childhood it starts to be a reliable predictor of intelligence later in life and in adulthood it hardly varies anymore.

Variations in Intelligence
The distribution of IQ normally yields a curve that is bell-shaped, a normal distribution. While with age fluid intelligence tends to decline, that is the acquiring of new skills or solving novel problems, however crystallized intelligence applying already acquired knowledge, might actually increase.

The Intellectually Gifted
A high IQ reveals potential but it does not guarantee success. Lewis Terman selected a group of children with exceptionally high IQs of 140 and higher, they showed to maintain this high score also in adulthood and all showed an extremely high rate of success. While the average values of IQ do not seem to be related to IQ, the extremes seem to be highly correlated with it. However, not all were successful, the distinguishing feature being the education by their parents. Those that were raised by educated parents that valued education and learning tended to do so as well. In general, it was an intellectual determination that made them stand out, a desire to excel and to know, motivation and persistence were defining characteristics of this group of people.

Intellectual Disability
The savant syndrome describes a condition in which a person with limited measured intelligence shows exceptional mental abilities in one or several narrow areas.

People who score below average on one of the commonly used intelligence tests are called intellectually disabled (it begins at an IQ score of 70 and below). In order to determine such a condition the person's ability for adaptive behavior meaning basic skills to lead an independent life are also taken into account and are expected to gain even more salience as opposed to IQ.

In 30-40% of the cases in which such a condition occurs there is no direct biological explanation, this is especially true for cases of mild intellectual disability. Sometimes there are other cases in the family although it has been found that such cases of familial intellectual disability mostly relate to an impoverished environment of the affected.

Half of all cases of intellectual disabilities have physical or organic causes. They may be caused by birth defects, fetal damage, metabolic disorders and finally genetic defects.

One of these conditions is the Down Syndrome which occurs in about 1 out of 800 babies. It is caused by an extra 21st chromosome, which is why it is often referred to as trisomy-21. This is caused by defect in the sperm or egg cell of one parent and is thus genetic but not hereditary. It leads to severely limited mental abilities and a shorter life expectancy of about 49 years.

The fragile X syndrome is the second most common form of a genetically caused mental disability. It is hereditary and sex-linked, with boys suffering much more often than girls from this syndrome. Affected people tend to have long, thin faces and big ears, they are above average tall during adolescence but below average in adulthood. While they experience only mild intellectual disabilities during childhood they are severely mentally disabled during adulthood.

Phenylketunoria (PKU) is also a genetic disease causing phenylperuvic acid to collect in their bodies and impairment of dopamine. If it is not treated early enough it can lead to severe mental disabilities starting from the age of three. Affected children are placed on a special diet which usually helps to avoid an occurrence of mental disabilities.

In Microcephaly the affected suffer from an extremely small skull which forces the brain to develop in a very limited space causing severe mental disabilities. Hydrocephaly in contrast causes a build-up of cerebrospinal fluids in the brain which can damage the brain and enlarge the head. A common treatment is draining the fluids into the abdomen and thus preventing severe disabilities, although people still tend to score below average on intelligence tests. A lack of the hormone thyroid leads to a disease called cretinism which can also be caused by a lack of iodine, it makes physical and intellectual growth come to a halt and is irreversible. It can, however, be prevented by administering artificial thyroid hormones to the affected children.

Heredity and Environment
Twin studies have found that IQ seems to correlate to a great degree with genetics. IQs of monozygotic twins are very similar even if they are separated and raised in different environments. On the other hand, it was shown that a biological child and an adopted child raised by the same mother had very similar IQs as well, the genetic inheritance of the mother seemingly not having an effect. In general it has been found that children in homes with a low socioeconomic status develop a lower IQ than children in homes with higher socioeconomic status.

The Flynn Effect describes how across 14 nations there has been an increase in an average of 15 IQ points in the last 30 years, an increase to stark and to be rapid to be explained by genetics and rather attributable to a change in environment conditions.

It is widely acknowledged that both heredity and environment play a role in determining a person's IQ, however while it seems that there is no low limit, below which an IQ might fall in an especially deprived environment, it seems that heredity does impose an upper limit past which an IQ cannot develop.

Psychometric Analysis - intelligent alternatives to the 'g'
There are a number of different approaches to IQ and more specifically to measuring it.


 * 1) Some scientists look at the Nervous System, postulating that it might be superior capacities for processing information in the nervous system which distinguish intelligent people. In order to test this hypothesis they measure people's reaction time to stimuli. Overall, people with a higher IQ also showed a superior processing speed in such tests.
 * 2) The cognitive perspective on this question takes into account that intelligent behavior in general is an expression of good thinking skills, composed of
 * 3) neural intelligence, speed and efficiency of the nervous system
 * 4) experiential intelligence, specialized knowledge and skill that are acquired over time
 * 5) reflective intelligence, an ability to become aware of one's own thinking habits
 * 6) Artificial Intelligence, tries to replicate the traits commonly seen as intelligent in humans in computers. So far they have not come to resemble human intelligence since they only perform well on tasks which work following a fixed set of rules or require speed, persistence and a capacity for vast memory.
 * 7) Multiple Intelligences, departs from the notion that the g-factor tests only very specific mental abilities useful and required in school but not to ultimately have success in life. That is why researchers suggest that there might in fact be various forms of intelligence, Howard Gardner proposed a set of 8:
 * 8) linguistic abilities, language
 * 9) Numeric abilities, logic, maths
 * 10) pictorial abilities, visual and spatial
 * 11) musical abilities
 * 12) physical abilities, athletics, bodily-kinesthetics
 * 13) Intrapersonal, self-knowledge
 * 14) Interpersonal, social abilities
 * 15) Naturalist, any ability related to understanding the natural environment

=Chapter 10 - Emotions and Motivation=

Motivation - Forces that push and pull
Motivation is the dynamic of human behavior, referring to the way in which our actions are initiated, sustained, directed and terminated.

A simple model of motivation shows the following chain of events. The motivation starts with a need, or and internal deficiency, this leads to the development of a drive, an energized motivational state which leads to the initiation of actions, directed to reaching the goal thath satisfies the need.

Motivation can either be provoked by an internal need or by the external pull of a stimulus. The pull of a goal that is pursued is classified as its incentive value, its appeal beyond the mere ability to fulfill a need. Sometimes the incentive value of a goal is so high that it can induce motivated behavior in absence of an internal need. Usually actions are directed by a mixture of internal needs and external stimuli.

Motives for behavior can broadly be categorized into three categories


 * 1) Biological Motives, based on biological needs necessary to be fulfilled for survival
 * 2) Stimulus Motives, based on our need for stimulation and information
 * 3) Learned Motives, based on learned needs, drives and goals which are often inherently social n nature

Biological needs are important because they help maintain homoestasis, or the bodily equilibrium – a steady state where all inner body levels are at their respective optimal level. Motivations based on these biological needs vary also in a constant pattern over longer time spans, every 24 hours they follow the Circadian Rhythm. People with early peaks in their Circadian Rhythm tend to be day people, awaking early, while people with late peaks tend to be night people, awaking late and staying awake late.

Hunger – Pardon me, my Hypothalamus is growling
The Hypothalamus is the area in the brain most concerned with motives, directing hunger, thirst and sex drive among others. Relating to the motive of hunger it is important that the Hypothalamus is sensitive to the level of sugar in the blood and in addition to that receives signals from liver and stomach. The lateral Hypothalamus is the area responsible for initiating eating processes. One of the signals the lateral Hypothalamus receives comes from the stomach in the form of an increased production of a hormone called ghrelin that activates the later Hypothalamus. The ventromedial Hypothalamus is part of the system concerned with determining when enough food has been eaten, damage to this brain area can lead to dramatic overeating.

The brain installs a set point which controls the weight of a person over long time spans. When the body weight goes beyond the set point a constant feeling of hunger follows, if it exceeds the set point the fat cells in the body release leptin which inform the Hypothalamus to reduce the amount of food consumed. No way has yet been found to willingly alter the set point which remains stable even through adult life.

Another chemical called glukagon-like peptide (GLP-1) is also involved in managing starting and stopping to eat. It is released by the intestines and reaches the brain through the blood stream. The paraventricular nucleus in the Hypothalamus also regulates sugar level in the blood by influencing starting and stopping to eat.

Taste aversion, the dislike of a certain food is often caused by our deeply rooted biological preparedness to associate an upset stomach with previously eaten food, even though the two instances might have just been correlated with no direct causation.

Biological Motives Revisited – Thirst, Sex and Pain
There are two types of thirst
 * 1) Extracellular Thirst, caused by a loss of water surrounding the cells in the body, this type of thirst is caused by lack of both, water and minerals and can best be saturated with salty water
 * 2) Intracellular Thirst, caused by an excessive intake of salt which leads to an extraction of fluid from the cells themselves, it is best saturated by plain water

In contrast to thirst and hunger which respond to external stimuli but also internal cycles of needs, pain is an episodic motive, responding only to external stimuli. It leads us to either avoid or eliminate the source of discomfort.

The Sex Drive describes the strength of one's motivation to engage in sexual behavior. Sex Drive in men is related to the amount of androgens (hormones such as testosterone) supplied by the testes. In the women it is directed by the level of estrogen, however, when a woman's body produces higher levels of androgens her Sex Drive also increases accordingly. It is a non-homeostatic motivation, it can be aroused at anytime by anything and does not relate to the last time it was satisfied.

Stimulus Motives
Stimulus motivation is that which relates to the need for new stimulation and information. According to arousal theory such motives are also homoestatic, so we try to keep them at an optimal level at all times. Arousal here refers to any activation of the body or the nervous system. The theory further suggests that people learn to seek different optimal levels of arousal. Sensation seeking is a label for people who prefer high levels of stimulation.

The relationship between arousal and performance is best represented by an inverted U-function, meaning that high performance correlates with moderate arousal and both very intense and very low arousal correlate with low performance. The Yerkes-Dodson Law maintains that the ideal level of arousal varies with the complexity of the task. A simpler task is best solved with a high level of arousal while a more complex task is best solved with a lower level of arousal.

Learned Motives – The Pursuit of Excellence
The opponent-process theory suggests that whenever a stimulus provokes a strong emotional response such as joy, fear or anger, when it wears off exactly the opposite emotional response will be the result. When a stimulus is repeated we habituate and our emotional response to it becomes weaker. However, the contrasting emotion becomes stronger with repetition, so that the costs start wearing off but the pleasure is increased.

Social motives are acquired through processes of socialization and cultural conditioning. One of these typical learned needs is the need for achievement, the need to meet an internal standard of excellence. It differs from the need for power, the need to have impact on or control over other people.

Motives in Perspective
Abraham Maslow has proposed a hierachy of needs structured in the form of a pyramid in which some needs are more basic and others more powerful in nature. Biological needs are at the bottom of the pyramid as they tend to be prepotent over all other needs, before the need for survival is met there is hardly any other need we can consider. All four bottom layers of the pyramid are basic needs, they include the biological needs, safety and security, love and belonging, esteem and self-esteem. At the top of the pyramid we find the growth needs, the need for self-actualization. Such needs are referred to by Maslow as meta-needs, an expression of the tendency to strive to fully develop one's potential.

According to self-determination theory whenever someone freely chooses something for enjoyment or improvement of abilities the motivation to choose the activity is an intrinsic motivation. By contrast extrinsic motivation is rooted in external incentives, both positive in the form of rewards and negative in the form of punishment.

It has been shown that extrinsic motivation can sometimes even lower incentive to engage in an activity, especially excessive rewarding. This can also be caused when an activity is rewarded and by that turned from something that people enjoy into something that they have to do, motivation declines radically. While extrinsic motivation such as salaries may increase the quantity of work, the quality of work is largely increased with an increase in creativity, sparked by intrinsic motivation. Time pressure is another big factor that prevents creativity.

Inside an Emotion - How do you feel?
Emotion is characterized by physiological arousal, change in facial expression, posture and subjective feeling. Emotions are linked to a range of basic adaptive behaviors, behaviors which constitute a reaction to the environment, as such emotions may have negative effects but more often and primarily aid survival.

Typical physiological changes caused by emotions relate to heart rate, blood pressure, perspiration and the like. They are caused by enhanced activity in the sympathetic nervous system, primarily through the hormones, adrenaline and noradrenaline.

Emotional expressions are outward expressions of what a person is feeling. Emotional feelings, finally are a person's private emotional experience.

It is assumed that some emotions are more basic than others, Robert Plutchik has identified eight primary emotions: fear, anger, trust, joy, surprise, sadness, disgust, anticipation. Each of these primary emotions can vary in intensity. Moods are low intensity emotional states which can last over several hours. Moods are also closely tied to the body's Circadian Rhythm, when body temperature is low, mood tends to be low a well, whenever the body temperature is at its peak, mood tends to be good as well.

Positive and negative emotions are not necessarily mutually exclusive, they can just as well coexist. This is due to the fact that emotions are more or less divided between hemispheres, the left is responsible for positive and the right for negative emotions. Damage to the amygdala renders people incapable of both, experiencing emotion themselves and interpreting the emotional state of other people through indicators such as facial or body expression.

Physiology and Emotion
Strong emotions connected with physical reactions can kill people in two ways. First, if the sympathetic nervous system becomes too active and this results in excessive stress. Secondly, the parasympathetic rebound, the switching from the sympathetic to the parasympathetic nervous system, can be too strong. If the situation evokes a very strong response from the sympathetic nervous system, the counter attempt of the parasympathetic nervous system to calm the body might be so dramatic that it actually slows the heart until it stops beating.

Sometimes, devices called lie detectors are used to determine whether someone is telling the truth, however their reliability is more than doubtful. The real name of such an apparatus is polygraph. It works by connecting the subject to the machine, which measures heart rate, blood pressure, breathing and the galvanic skin response (perspiration). As it is it can only indicate general emotional arousal without being able to distinguish between fear and lying, anxiety or excitement. The usefulness of polygraphs is increased when they are used in combination with guilty knowledge tests, the subject is asked a question and multiple answers are given. It is believed that only the culpable person will show emotional arousal at one of the answers, indicating their guilt.

Expressing Emotions
Facial expressions for basic emotions such as fear, anger, surprise, happiness, disgust and sadness seem to be quite universal. The human face is able to produce around 20,000 different facial expressions. The reason that these can be interpreted quite rapidly and accurately by others is that facial expressions can be reduced to three general dimensions pleasantness-unpleasantness, attention-rejection and activation (arousal).

Emotions are dependent on culture, in some cultures negative emotions are less openly expressed than in others, in individualistic societies positive emotions connected with the individual are more commonly expressed than in collectivist societies. In Western cultures it is quite common that women express more emotions than men, men more often suffer from alexithymia, an inability to name an emotion. Men are raised and educated into this state and often suffer depression or addictive behavior as a result from their inability to connect with their own emotions.

Kinesics is the study of how emotions are conveyed through body movement, posture, gestures and facial expressions. The chameleon effect describes the way in which we unconsciously imitate the body language of the people we interact with. This comes with the tendency for us to like people who use a similar body language as we.

Illustrators, gestures people use to explain something tend to be used much less while people tell a lie. On the other hand, emblems gestures with a widely understood meaning, tend to increase while people tell a lie.

Theories of Emotions
=References=