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Kassin, S. (2001). Psychology. 3^rd ed. Upper Saddle River, NJ: Prentice Hall.

Glossary

					A
absolute threshold					The value at which a stimulus is detected 50 percent of the time.
accommodation					In developmental psychology, the process by which existing cognitive schemas are modified or changed by new experiences. In sensory psychology, accommodation is the process by which the lens focuses light on the retina: as muscles contract (when viewing objects close up) or relax (when viewing distant objects), the lens bulges or narrows, respectively.
acetylcholine					A neurotransmitter found in the brain, where it is involved in learning and memory, and in the spinal cord and body, where it is involved in the control of the skeletal muscles and organs.
achievement					Skills that are already learned, such as having learned a foreign language.
acquisition					The first stage of learning, in which a response first appears and then increases in frequency or strength.
action potential (Also called neural transmission.)					The electrochemical signals by which neurons exchange information within the nervous system. Neural impulses are triggered when the neuron becomes depolarized and sodium floods into the cell.
Activation-synthesis theory					This physiological theory of dreaming proposes that random neural messages during REM sleep activate the brain, which then synthesizes the messages based on past experience, memories, recent feelings, etc. in an effort to form some sort of coherent image, which is the dream we experience.
actor-observer effect					The tendency to attribute one's own behavior to the situation, but others' behavior to their disposition.
acupuncture					A procedure of pain reduction developed by the Chinese in which small needles are inserted into the body at strategic spots.
addiction					A common synonym for substance dependence.
adolescence					The period of life beginning with puberty and ending with the establishment of emotional and social independence from parents.
adrenaline					See epinephrine.
aerial perspective					In depth perception, the monocular cue in which objects far off in the distance appear hazy and less distinct than nearby objects.
aerobic exercises					Activities such as running, walking, bicycling, and swimming that stimulate and strengthen the heart and lungs, and, in turn, increase the body's efficiency in using oxygen.
aggression					Any action, verbal or physical, that is intended to cause harm.
agonists					Substances that increase the activity of neurotransmitters.
agoraphobia					The intense fear of being away from a safe place or a safe person; literally, a fear of open or public places.
alcoholism					A dependence on ethanol, which is the psychoactive agent in alcohol.
algorithm					A completely specified, step-by-step set of rules for solving a problem.
altruism					Unselfish concern for the welfare of another.
Alzheimer's disease					A brain disease typified by progressive deterioration of thinking, language, memory, and eventually physical abilities.
Amino acids					Organic molecules containing nitrogen in the form of ¯NH₂ and a carboxyl group, ¯COOH, bonded to the same carbon atom; the "building blocks" of protein molecules.
amnesia					The profound loss of once-demonstrated memory skills.
amphetamines					Stimulant drugs that tend to increase behavior and activity of the central nervous system by stimulating the release of dopamine and norepinephrine. In large doses, it can cause reactions, such as delusions (false beliefs) and hallucinations, resembling schizophrenia.
amplitude					The height of sound and light waves; determines intensity. Greater amplitudes mean brighter colors and louder sounds; smaller amplitudes mean less intense colors and softer sounds.
amygdala					The structure in the limbic system of the brain that is involved with the control of aggression and fear.
Anal stage					The second of Freud's psychosexual stages (from about 18 months to 3 to 4 years). During this stage, the primary erogenous zone is the anal region.
anorexia nervosa					An eating disorder characterized by a pathological fear of weight gain, an obsession with not eating food, and a refusal to eat. Often accompanied by excessive exercising.
antagonists					Substances that block or decrease activity of neurotransmitters.
anterograde amnesia					Loss of the ability to remember events that occur after a brain injury.
antisocial personality disorder					A disorder characterized by a failure to conform to standards of decency, repeated lying and stealing, a failure to sustain lasting, loving relationships, low tolerance of boredom, and a complete lack of guilt and anxiety.
antidepressants					A class of medications that relieve the symptoms of depression.
antipsychotic drugs					A class of medications that reduce many of the symptoms of schizophrenia.
anxiety					A sense of apprehension or doom that is accompanied by a number of physiological reactions, such as accelerated heart rate, sweaty palms, and tightness in the stomach. Considered a disorder if anxiety is constant or disabling.
anxiety disorder					An unrealistic and excessive anxiety that diminishes some aspect of a person's life.
Apgar score					The results of a test normally given to babies at one minute and five minutes after birth. Points are given based on performance in the following areas: Activity (muscle tone), Pulse, Grimace (reflex irritability), Appearance (skin color), and Respiration.
aptitude					The capacity or potential for learning.
archetypes					Universal thought forms and patterns that Jung believed reside in the collective unconscious.
argument					A set of statements that contains at least one conclusion and one reason for believing that the conclusion is true.
assimilation					The process by which new information about the world is modified to fit existing cognitive schemas.
Association areas					The portions of the cerebral cortex that are devoted to higher mental processes, including planning and decision-making.
associative strength					In classical conditioning, the connection between the conditioned stimulus (CS) and the unconditioned stimulus (UCS), or the degree to which the CS reliably predicts the UCS. In operant conditioning, the strength of the connection between a response and its consequence.
astigmatism					A visual disorder caused by defects in the spherical shape of the cornea. When the cornea is misshaped, visual images are not focused equally on different parts of the retina.
attachment					The important social and emotional bond that forms between infants and responsive caregivers and spans both time and space.
attitude					An evaluative response to any person, object, or situation based on our beliefs and their accompanying emotions.
attribution theory					The theory that attempts to explain how people infer the causes of their own and other people's behavior.
auditory canal					The tubelike structure connecting the pinna with the tympanic membrane, and through which sound waves enter the ear.
auditory nerve					The bundle of neurons that carries nerve impulses and their auditory information from the hair cells in the ear to the brain.
authoritarian parents					Those who establish firm rules for their children and expect them to be obeyed without question. Disobedience is met with punishment rather than understanding or reasoning.
authoritative parents					Those who establish rules and enforce them, but not through punishment alone. Authoritative parents seek to explain the relationship between rules and punishment to their children.
automatic processing					The encoding of information without conscious effort.
autonomic nervous system					The part of the peripheral nervous system that controls bodily processes over which we generally exert no conscious control, such as heart rate, respiration, and digestion.
availability heuristic					A heuristic for judging frequencies of events that relies primarily on the importance of the information that is most readily and easily available to the person solving the problem.
aversion therapy					A form of treatment in which the client is trained to respond negatively to a neutral stimulus that has been paired with an aversive stimulus.
axon					The long pipelike fiber projecting from the nerve cell body to the axon terminals that passes messages along to other neurons, glands, or muscles.
axon terminal					The end of a neuron's axon; where messages are transmitted across the synapse to the next neuron's dendrites.
					B
Barnum Effect					The deliberate use of vague terms to make individuals believe that a prediction or description applies to them.
Basic orientations					Horney's idea that different sets of personality characteristics correspond to the strategies of moving toward others, moving against others, and moving away from others.
Basilar membrane					A structure in the ear that runs nearly the entire length of the cochlea and functionally divides the cochlea into upper and lower divisions. The hair cells are embedded in the basilar membrane.
Behavior					The actions of organisms that can be observed directly by others.
Behavior assessment					Techniques for assessing personality that focus on what an individual actually does, not just what he or she reports.
Behavior genetics					Study of the relative effects of genetics and environment on an individual's behavior and cognitive processes.
Behavior modification					A form of behavior therapy based on operant and classical conditioning principles that teaches clients how to act differently.
Behavior therapy					The application of principles derived from behavioral research for the alleviation of psychological problems.
behavioral perspective					A view in psychology holding that behavior is caused mostly by environmental variables rather than biological ones.
Behaviorism					The school of psychology often associated with Watson, who argued that observable behavior and not mental processes were the proper subject matter of psychology.
belief-bias effect					The improper evaluation of the validity of a conclusion due to the influence of pre-existing beliefs.
Big Five					See five-factor theory.
Binocular depth cue					A depth cue that requires the use of both eyes to be able to use its information about depth.
Binocular disparity					A binocular depth cue that arises as a result of the two eyes sitting in different places on our faces. This fact causes objects nearer and farther than what we are looking at to fall on a different position of each retina.
biological clock					The order in which our important biological events, such as birth, puberty, and birth of a first child, take place.
biological perspective					A view in psychology that behavior is influenced mostly by genetic, physiological, and other biological processes rather than environmental variables.
biomedical therapy					Treatment of psychological problems by directly altering the physical functioning of the brain, such as through drugs or psychosurgery.
Biopsychology					The study of the nervous system and its relation to behavior.
Bipolar disorder					A mood disorder suffered by a person whose life is disrupted by a cycle of manic episodes followed by major depressive episodes.
blind spot					The point on the retina at which the optic nerve exits the back of the eye, creating a hole in our vision.
blood-brain barrier					A shield of tiny capillaries in the brain that protects brain cells by screening out harmful substances.
boolean logic					Named after the nineteenth-century mathematician George Boole, Boolean logic is a form of algebra in which all values are reduced to either TRUE or FALSE. Boolean logic is especially important for computer science because it fits nicely with the binary numbering system, in which each bit has a value of either 1 or 0. Another way of looking at it is that each bit has a value of either TRUE or FALSE.
Boolean operators					Originally described by George Boole, thses operators allow you to combine keywords together to create or preform a more specific search. Typical Boolean operators are: AND, OR, NOT(in some search tools, AND NOT). Boolean operators must be capitalized. Not all search tools accept Boolean operators.
bottom-up processing					Processing of a pattern that begins at the level of the receptors and proceeds in an orderly fashion through specialized cells in the visual cortex.
Brainstem					The most posterior portion of the vertebrate brain; includes medulla, pons, and midbrain. Also called central core.
Brightness					Intensity of light; determined by amplitude.
Brightness contrast					The phenomenon in which a color appears brighter as the background becomes darker.
Broca's area					The portion of the left frontal lobe that is involved in the motor production of speech.
bulimia					An eating disorder in which sufferers binge periodically, consuming enormous quantities of food, and then either force themselves to regurgitate or use laxatives to rid their bodies of the food.
bystander effect					The reduced tendency of people to offer help in an emergency situation when others are present.
					C
cannabis					The active ingredient in marijuana, from the cannabis sativa plant; a psychedelic drug with effects similar to LSD.
Cannon-Bard theory					The theory proposing that the experiencing of emotion and the experiencing of physiological arousal are independently controlled by the brain but happen simultaneously during emotional arousal.
case study					An intensive investigation of a single individual over an extended period of time based on the use of observational techniques.
catatonic schizophrenia					A type of schizophrenia characterized primarily by disorders of motor behavior: alternation between uncontrolled excitement and immobility, with one or the other extreme dominating.
category clustering					The recalling of words according to semantic categories.
catharsis					Freud's term; used to describe the process in which pent-up energy is released or purged. He believed displacement and sublimation could provide such an outlet.
cell body					The part of the neuron that contains the nucleus and other structures that control the moment-to-moment functioning of the cell.
central core					See brainstem.
central nervous system					The brain and spinal cord.
central tendency					A measure of the typical score or performance.
central traits					Personality attributes that seem to be the most representative of an individual.
cephalocaudal principle					The idea that growth of the body proceeds from head to torso to feet; control over the upper body takes place before control over the lower body.
cerebellum					A structure located just behind and slightly above the medulla that is involved in the regulation of coordinated movement.
cerebral cortex					The large convoluted mass of brain tissue located just beneath the skull. This tissue, which is the most recent achievement of brain evolution, is involved in complex cognitive processes such as reasoning and decision-making.
chromosomal aberration					The rearrangement of genes within or between cells or a change in the total number of chromosomes.
chromosomes					The rodlike structures made of DNA that are found in the nuclei of living cells; contain the genes.
chunk					The representation in memory of stimuli as a unit or meaningful concept.
circadian rhythm					The daily cycle of activities of the nervous system—for example, sleeping and waking and temperature. Circadian rhythms wax and wane over the course of each 24-hour period.
classical (or Pavlovian) conditioning					The form of learning in which an association is formed between one stimulus or event and another stimulus or event.
clinical psychologist					A psychologist who assesses, researches, and/or seeks to correct abnormal behavior.
closure					A principle of perceptual grouping in which an object tends to be perceived as a whole even though a part of it is missing.
cochlea					A bony, coiled, fluid-filled chamber in the inner ear that houses the auditory receptors.
cognition					The full range of mental activities used to represent and process knowledge, including perception, memory, thought, and the use of language.
cognitive appraisal					Our perception of a stressful situation. Cognitive appraisal is a two-stage process. In the first stage we evaluate the nature of the threat. If we decide that the threat is real, we pass to the second stage, during which we assess whether we have the resources necessary to cope adequately with the stressor.
cognitive behavior therapy					A method of treatment that focuses on altering the client's thoughts, beliefs, and perceptions.
cognitive dissonance theory					A theory that proposes people are motivated to reduce the anxiety produced by inconsistent cognitions and behaviors, for example by changing their attitudes to match their actions.
cognitive economy					The minimization of the amount of effort and time required in the processing of stimuli.
cognitive perspective					A view in psychology that emphasizes the study of how organisms process information about their environment.
cognitive processes					Unobservable mental activities such as thinking, sensing, and perceiving.
cognitive reappraisal					A coping strategy in which the individual alters his or her perception of the threat posed by a stressor to reduce stress.
cognitive restructuring					In therapy, the process of replacing the patient's negative thoughts with more constructive ways of thinking.
cohorts					The people born in the same year or time period.
collective unconscious					According to Jung, the part of the unconscious that contains memories and ideas inherited from our ancestors over the course of evolution.
commitment					According to Marcia, a decision based on consideration of alternative goals and values that leads to a specific course of action—the teenager is "committed'' to thinking and acting in a manner consistent with how the crisis has been resolved.
community psychology					A movement focused on addressing psychological problems through an assessment of the sociocultural context in which the problems develop. Aims to prevent psychological disorders by improving the social environment as well as providing accessible community mental health programs.
competition					A striving, or vying with others who share the same ecological niche, for food, mates, and territory.
complementary colors					Pairs of primary colors (red and green or yellow and blue) that produce a white or gray when mixed together.
compliance					A change in one's behavior or beliefs to match some other's as the result of social influence.
compulsion					An irresistible impulse to repeat some action over and over even though it serves no useful purpose. Compulsions are often behavioral responses to a specific obsession.
computational metaphor					The metaphor used by cognitive psychologists that likens human cognition to a computer program.
concept					A grouping of similar objects, events, or people into mental categories.
concrete operational period					Piaget's third stage of cognitive development (roughly ages 7 to 11), in which children develop the ability to understand the conservation principle and other logical concepts, such as categorization.
concurrent validity					A measure has concurrent validity when it provides an accurate and reliable measure of a trait that an individual possesses at present. For example, a measure of shyness has concurrent valid if it assesses how shy an individual is at the time the measure is taken.
condensation					The part of Freud's dream work process where he believed we combine several objects or people into a single symbolic dream element as a part of the process of masking the true meaning of our dream.
conditioned response (CR)					In classical conditioning, the learned response to the CS.
conditioned stimulus (CS)					In classical conditioning, any neutral stimulus paired with the unconditioned stimulus that eventually elicits a response.
conditions of worth					According to Rogers, our perception of the criteria we must meet in order to be worthy of positive regard from others.
conduction hearing loss					The obstruction or destruction of the conductive structures of the ear, specifically, the external auditory canal, tympanic membrane, and ossicles.
cones					Color-sensitive receptors found primarily in the fovea, although some may be found in the retina's outer region or periphery.
confederate					A person acting as a subject in an experiment, but who is really an assistant of the researcher.
confidentiality					Maintaining the privacy of the identity of subjects who participate in research or patients who undergo therapy.
confirmation bias					People's tendency to search for instances that confirm their beliefs rather than to search for evidence that falsifies those beliefs.
conformity					Thinking or behaving in a manner that is consistent with the norms of a social group.
confound					A situation in which two or more variables differ at the same time.
confounding variables					Variables other than the independent variable that can influence the value of the dependent variable.
conservation					In development, the understanding that specific properties of objects (number, volume, etc.) remain the same despite apparent changes in the shape or arrangement of those objects.
constructs (intervening variables)					Abstract variables that cannot be observed directly, such as gravity and intelligence.
continuous reinforcement schedule					A reinforcement schedule in which a reinforcer is delivered for each response.
control group					The group of subjects in an experiment that is either not exposed to the independent variable or otherwise provides a base of comparison with the experimental group.
conventional level					The second level in Kohlberg's theory of moral development, during which children's moral reasoning becomes subject to conformity.
convergence					The muscle movements that cause the eyes to look inward; provides us with a depth cue based on how far inward we have to look to focus on a given object.
conversion disorder					The somatoform disorder that involves the actual loss of bodily functions such as blindness, paralysis, and numbness due to excessive anxiety.
cornea					The transparent fluid-filled cover at the front of the eye, through which light enters.
corpus callosum					A large cable of axons that connects and allows communication between the two hemispheres of the brain.
correlation					The statistical term used to describe the degree of relationship between two or more variables.
correlation coefficient					A statistical expression of the amount of correlation between two variables, with a value that ranges from –1.00 (perfect negative correlation) to +1.00 (perfect positive correlation).
cortex					(1) The outer, as opposed to the inner, part of an organ, as in the adrenal gland. (2) In a stem or root, the primary tissue bounded externally by the epidermis and internally by the central cylinder of vascular tissue.
countertransference					The process by which the therapist projects his or her emotional issues onto the client.
covariation rule					The attributional rule in which certain events are seen as occurring together in time.
CR					Abbreviation of conditioned response.
creativity					The generation of novel and useful solutions to problems.
crisis					According to Marcia, a period during which the adolescent struggles intellectually to resolve issues related to personal values and goals.
critical (or sensitive) period					The period of time shortly after birth when certain learning and growth must occur for normal development to continue.
critical thinking					The use of cognitive skills or strategies that increase the probability of achieving a desirable outcome and the disposition to use those skills in both familiar and novel contexts.
cross-sectional approach					A research design used to test or observe different individuals of various ages at the same point in time.
crystallized intelligence					A kind of intelligence that reflects both formal education and the "seat of the pants'' learning that comes in everyday life.
CS					Abbreviation of conditioned stimulus.
cultural evolution					The adaptive changes of cultures to recurrent environmental pressures over time.
cyclothymia					A mood disorder suffered by a person who experiences relatively mild manic episodes (called hypomania) alternating with relatively mild periods of depression but can still carry on the normal responsibilities of life.
					D
dark adaptation					The process of our eyes adapting to decreasing levels of illumination.
data					Scientific information usually obtained by numeric measurement.
debriefing					A procedure of informing subjects of the true nature and purpose of the research after all data have been collected.
decibel (dB)					The unit of measurement for studying a sound wave's amplitude and loudness.
deductive reasoning					A form of reasoning in which a conclusion is implied by two or more statements.
deep structure					The structure underlying a sentence that is directly related to the meaning of the sentence.
defense mechanisms					According to Freud, mental tactics that the ego uses to insulate itself from threatening ideas, perceptions, emotions, and instincts.
degradation					The process by which neurotransmitters are destroyed by enzymes in the synaptic gap.
delusions					False beliefs maintained in the face of no evidence or contrary evidence.
demand characteristics					Factors in an experiment that cause subjects to behave in a manner consistent with what they believe the study is about.
dementia					A loss of mental functioning.
dendrites					Tiny, treelike projections jutting out from the cell body in the neurons which receive nerve impulses from neighboring neurons or receptors.
denial					According to Freud, a defense mechanism that blocks from consciousness threatening perceptions of the real world.
deoxyribonucleic acid					See DNA.
dependent variable					The variable that is measured in an experiment. In psychological research, the dependent variable is always behavior.
depolarization					The first part of an action potential when the inside of the axon goes from n70 mv to a slightly positive value.]
depressants					Psychoactive drugs that slow down the nervous system's activities, producing drowsiness and sedation.
depression					A negative mood characterized by a prolonged period of sadness, lack of energy, low self-worth, guilt, and related feelings.
depth cues					Those aspects of any stimulus situation that indicate how far an object is from the observer or other objects.
depth perception					The ability to perceive the world in three dimensions and thereby judge the distance of objects from us or other objects.
descriptive statistics					Statistics used to describe a particular set of data, such as the mean or median.
Diagnostic and Statistical Manual of Mental Disorders–IV (DSM–IV)					The current and most widely used manual for classifying psychological disorders. The DSM-IV is a classification system that describes an individual's psychological condition based on five different types of information, which are called axes.
diathesis-stress model					The idea that psychological disorders, such as schizophrenia, are due to the interaction of both a genetic disposition (diathesis) and environmental factors (stress).
difference threshold					The minimal change in stimulation that can be reliably detected 50 percent of the time.
diffusion of responsibility					An explanation of the bystander effect stating that when several bystanders are present, no one individual assumes responsibility for helping the victim(s).
discounting rule					The presence of several competing attributions for the same behavior.
discrimination					In classical conditioning, distinguishing one stimulus from another. In operant conditioning, responding in the presence of only certain kinds of stimuli—those associated with reinforcement or with punishment. In social psychology, the differential treatment of people based on their membership in a particular ethnic, religious, gender, or other group.
discriminative stimulus					In operant conditioning, the preceding event or stimulus that sets the occasion for responding because in the past that behavior has produced certain consequences in the presence of that particular stimulus.
disorganized schizophrenia					A type of schizophrenia characterized primarily by disturbances of thought and a flattened or silly affect. Behavior is often inappropriate and absurd; language is incoherent.
displacement					According to Freud, a defense mechanism in which feelings of hostility and aggression are channeled toward acceptable or less threatening persons or objects.
dissociative disorders					A class of rare disorders in which anxiety is reduced by a sudden disruption in consciousness, which, in turn, produces changes in one's sense of identity.
dissociative identity disorder					A rare dissociative disorder involving the emergence of two or more complete and independently functioning personalities in one person, though only one is dominant at any given time. (Formerly called multiple personality disorder.)
distal stimuli					Stimuli that are outside our bodies and do not impinge directly on our sense receptors.
distinctiveness					In social psychology, the extent to which a behavior is a response to a specific stimulus but not to others.
divergence					Definition to come.
dizygotic twins					Fraternal twins. Dizygotic twins develop from the separate fertilization of two ova.
DNA					Deoxyribonucleic acid. Genetic material found in the cells of most living things.
door-in-the-face technique					A compliance technique in which an unreasonable offer is followed by a more reasonable offer.
dopamine					A neurotransmitter that plays a role in brain regulation of movement, cognition, and emotion. Extremely high levels of dopamine produce symptoms of schizophrenia; extremely low levels produce symptoms of Parkinson's disease.
Doppler effect					Changes in wave frequency (light, sound, or radio) relative to the movement of the observer and the wave source.
double-blind					An experimental procedure for controlling experimenter expectancy in which neither the person conducting the experiment nor the subjects know the purpose of the study or to which group subjects have been assigned.
Down's syndrome					A genetic disorder caused by a chromosomal aberration resulting in an extra 21st chromosome.
dream interpretation					According to Freud, the evaluation of what he believed was the underlying meaning of dream content.
dream work					The process by which Freud claimed we mask the true meanings of our dreams. He proposed that we use condensation to combine several objects or people into a single symbolic dream element, and displacement to shift the focus of the dream away from the important elements, and thus distort or disguise the true meaning of the dream.
drive					A state of internal tension or arousal caused by an unsatisfied need.
drug therapy					The treatment of psychological problems with chemical agents.
DSM—IV					Abbreviation of Diagnostic and Statistical Manual of Mental Disorders–IV.
dual center theory of eating					The idea that the lateral hypothalamus and ventromedial hypothalamus work in concert to control eating.
dyslexia					A disturbance of the ability to read, sometimes characterized by inverted letters or words.
dysthymia					A mood disorder suffered by a person who experiences mild, persistent depression but can still carry on the normal responsibilities of life.

					E
ear drum					See tympanic membrane.
ecosystem					A system of interdependent relationships among organisms and between organisms and their physical environment.
ECT					Abbreviation of electroconvulsive therapy.
EEG					Abbreviation of electroencephalogram.
effortful processing					Information processing into memory that requires practice or rehearsal.
ego					According to Freud, the ego serves as the general manager of personality; it makes the decisions regarding the pleasures that will be pursued at the urging of the id, and the moral dictates of the superego that will be followed.
egocentric					A characteristic of preoperational children such that they are unable to see the world from any point of view but their own.
elaborative rehearsal					The processing of information on a deeper or more meaningful level than mere repetition.
electroconvulsive therapy (ECT)					A form of treatment for severe depression that involves passing small amounts of electric current through the brain to produce seizure activity.
electroencephalogram (EEG)					An amplified tracing or recording of the brain's electrical activity.
embryonic stage					The second stage of prenatal development, during which the heart begins to beat, the brain starts to function, and most of the major body structures begin to form.
emotions					Moods or feelings. Felt internal conditions that change from time to time largely as a function of things that happen to us.
empirical knowledge					Knowledge that is obtained from carefully observing and measuring behavior under highly controlled conditions.
empty chair technique					A therapy procedure in which the client imagines that he or she is talking to someone sitting in an empty chair close by.
encoding					The active process of putting stimuli into a form that can be used by our memory system.
encoding specificity					The principle that how we encode information may determine our ability to retrieve it later.
endocrine system					A slow-acting communication network composed of endocrine glands. These glands stimulate other glands and organs via hormones.
endorphins					Natural, opiate-like neurotransmitters associated with pain control and pleasure.
enkephalins					A class of neurotransmitters that appear to be involved in the body's ability to tolerate and mediate pain.
epigenetic principle					The idea that human development proceeds according to a biologically determined agenda based on two factors, biology and culture. Biological factors exert their influence at critical points (conflicts) during the individual's maturation; the culture in which one lives provides the context in which the individual resolves the conflict.
epinephrine					Hormone released by the adrenal glands, on orders from the autonomic nervous system, during stress response. Also known as adrenaline.
episodic drinking					Consuming five or more (four for women) alcoholic drinks on one occasion; also called "binge" drinking.
episodic memory					A type of memory found in long-term storage that serves as a record of our life's experiences. Events stored there are quite literally autobiographical.
erectile dysfunction					The inability to produce or maintain an erection.
essential questions					These questions require decision making or the development of an action plan. The answer to an Essential question may require the synthesis of many pieces of information. These questions may have personal meaning for you, and they certainly make you think. You often gain personal insight into a problem by trying to answer an Essential question.
etiology					A general term for describing the causes of a disorder.
eugenics					A word, based on a Greek term for "well-bred,'' that Galton used to describe the movement he founded to study and promote the principles of artificial selection in humans.
evolutionary psychology					A view in psychology that considers how natural selection and adaptation have affected our ancestors and how these forces might help explain some of our behaviors and cognitive processes today. Looks at group effects rather than individual effects.
exhibitionism					A sexual disorder where the displaying of one's genitalia to a stranger in a public place is used to obtain sexual pleasure.
expectancy					The individual's belief or perception that a specific consequence will follow a specific action, or that one event will reliably follow another event.
expectancy theory					The theory that an individual's anticipation or expectancy of the reward motivates his or her behavior.
experiment					A research method in which the investigator manipulates independent variables and measures their effects on dependent variables.
experimental group(s)					The group(s) of subjects in an experiment exposed to the independent variable.
experimenter expectancy					An experimenter's beliefs about the outcome of an experiment which may be inadvertently communicated to the subject and influence the subject's behavior.
expert system					A computer program that, like a human expert, uses heuristics and knowledge about the world to solve problems.
external attribution					The explanation of a behavior as caused by external forces or factors.
extinction					The weakening of a learned response. In classical conditioning, the procedure of no longer presenting the unconditioned stimulus (UCS) with the conditioned stimulus (CS) after conditioning of a response. In operant conditioning, any procedure in which a reinforcer is no longer presented following a response.
extrinsic motivation					Externally motivated; driven by a need to please others or perform to others' standards.
extravert (also extrovert)					Person who directs interests outward to other people and things.

					F
face validity					A measure has face validity when it appears to be a valid measure of what it purports to be measuring.
facial feedback hypothesis					The idea that feedback from our facial muscles helps us experience emotion by providing us with information about the emotion.
factor analysis					A statistical technique developed by Spearman for determining the correlation of different test questions to each other.
falsifiability					The ability to prove that a statement of inference is false.
family therapy					Therapy in which the family, rather than any particular family member, is viewed as the client.
farsightedness					See hyperopia.
FAS					Abbreviation of fetal alcohol syndrome.
feature analysis					The recognition of an object based on the distinctive characteristics or components that, because of the specific manner in which they are arranged, define that object.
feature detectors					Neurons in the visual cortex that are excited by particular patterns of light, such as lines and angles of different sizes and shapes.
fertilization					The union of a sperm and ovum resulting in conception.
fetal alcohol syndrome (FAS)					The serious side-effects in a baby produced by a pregnant woman's consumption of alcohol. These effects may include both pre- and postnatal growth deficits, facial deformities, brain and central nervous system abnormalities, and deformation of the heart.
fetal stage					The third and final stage of prenatal development. It begins with the appearance of bone and ends with birth.
fetishism					A sexual disorder where inanimate objects are used to obtain sexual pleasure.
FI					Abbreviation of fixed-interval schedule.
figure-ground relationship					An organizational principle of Gestalt psychology describing our tendency to perceive some objects, called figures, as standing out from their surroundings, called the ground.
five-factor theory					The trait theory that specifies five basic personality traits: Extraversion, Emotional Stability (also called Neuroticism or Anxiety), Openness, Agreeableness, and Conscientiousness. Also called the Big Five.
fixation					In Freud's psychoanalytic theory, an unconscious obsession with an erogenous zone resulting from failure to resolve the crisis associated with the corresponding stage of psychosexual development. In problem-solving, the tendency to view a problem solely in one particular way.
fixed-action pattern					A species-typical behavior characterized by a highly stereotyped pattern of responses.
fixed-interval (FI) schedule					A reinforcement schedule that provides reinforcement after a fixed amount of time has elapsed since delivery of the previous reinforcer.
fixed-ratio (FR) schedule					A reinforcement schedule that provides reinforcement after the organism has emitted a fixed number of responses.
flavor					A food or drink's taste, consistency, temperature, texture, and smell.
fluid intelligence					A kind of intelligence that reflects innate capacity for reasoning, problem solving, and remembering.
follicle-stimulating hormone (FSH)					In males, FSH stimulates the manufacture of sperm and in females FSH prepares the ovaries for ovulation.
foot-in-the-door technique					A compliance technique in which a small, reasonable request is followed by a larger, burdensome request.
formal operational period					The fourth and final of Piaget's stages, which begins roughly at age 11. During this stage, individuals first become capable of more formal kinds of abstract thinking and hypothetical reasoning.
foundation questions					These questions ask for facts that help you to answer Essential questions. These questions are often "wh" questions (who, what, where, when). Foundation questions provide the facts for the synthesis of the answer to the Essential question. Information found by answering Foundation questions is then used to build an answer to the Essential question being asked.
fovea					A small region (less than a square millimeter) in the center of the retina. It has only cones and is capable of seeing the finest details and clearest images. When we "look at" an object it falls on the foveas of both eyes.
FR					Abbreviation of fixed-ratio schedule.
free-association					Freud's psychoanalytic procedure, in which the client is encouraged to speak freely, without censoring possibly embarrassing or socially unacceptable thoughts or ideas.
frequency distribution					A listing or graph of all the possible values of a variable, and how many subjects actually obtained each of these values.
frequency theory					The theory of pitch that proposes that the entire basilar membrane vibrates in synchrony with the frequency of sound waves striking the ear. These vibrations are then transduced to an equivalent number of neural impulses that are channeled to the brain.
Freudian slips					Mistakes in speech that Freud believed reflect unconscious motivations and wishes.
frustration-aggression hypothesis					When individuals are frustrated they are likely to become aggressive.
FSH					Abbreviation of follicle-stimulating hormone.
functional fixedness					An example of a fixation. The tendency to limit possible solutions by using objects only in the way that they have been traditionally used.
functionalism					The school of psychology that studies the mind's role in helping organisms adapt to their environment.
fundamental attribution error					The tendency to apply dispositional rather than situational attributions to other people's behavior.
					G
g					The general ability that is purported by some theorists to be common to all intellectual tasks.
GABA (gamma-amino butyric acid)					The main inhibitory neurotransmitter found in the brain. Without GABA the brain would be overrun with excitatory neural impulses, which would lead to convulsions and seizures.
GAS					Abbreviation of general adaptation syndrome.
gate-control theory					A theory stating that our perception of pain is determined by the interplay of the nerve fibers that carry information about pain to the brain. Large, fast fibers close a neural gate through which nerve impulses carrying information about pain must pass on their way to the brain. Small, slow fibers open the gate.
gender					The individual qualities of a person, both biologically and environmentally influenced, that a given culture uses to define a person as a male or female.
gender identity					An individual's private sense of being a male or female. In most cases, one's gender identity matches one's biological gender.
gender roles					Cultural expectations for how men and women should think and behave.
gender typing					The learning of the attitudes and behaviors of a masculine or feminine gender identity and role.
general adaptation syndrome (GAS)					The model proposed by Selye to describe the body's adaptation to chronic exposure to severe stressors. Basically, the body passes through an orderly sequence of three physiological stages: the alarm stage, the stage of resistance, and the stage of exhaustion.
generalization					In classical conditioning, conditional responses elicited by stimuli that resemble the conditioned stimulus (CS) used in training. In operant conditioning, generalization means that once a response has been reinforced in the presence of a discriminative stimulus, other similar stimuli may also serve as discriminative stimuli for the same response.
generalized anxiety disorder					Chronically high levels of anxiety that are not specific to any one source.
genes					The small units of DNA that are located on chromosomes.
genetic program					The genetic instructions an organism inherits at birth.
genital stage					Freud's fifth and final psychosexual stage (from puberty through adolescence). During this stage, the adolescent experiences adult sexual desires. The id and superego once again become active, forcing the ego to find socially acceptable solutions to sexual or aggressive urges.
genotype					An organism's genetic make up.
Gestalt psychology					The school of psychology that studies the organization of cognitive processes, particularly perceptual processes.
Gestalt therapy					A form of therapy that emphasizes the unity of mind and body by teaching the client to "get in touch'' with bodily sensations and emotions long since hidden from awareness.
glial cell					A cell in the nervous system that binds neurons together.
glutamate					A neurotransmitter that increases nervous system activity.
good continuation					A principle of perceptual grouping in which objects are perceived to be constructed of smooth continuous features rather than discontinuous ones.
graphology					The analysis of the shape and spacing of the words and letters in your handwriting to assess and predict your personality traits.
greater convergence					Definition to come.
group therapy					Therapy in which two or more clients meet simultaneously with a therapist, sharing and discussing problems within a supportive and understanding environment.
					H
habituation					A decreased response to a repeated stimulus.
hair cells					The auditory receptors in the ear. Whenever the basilar membrane vibrates, it forces the hair cells upward against another membrane, bending them in a shearing motion. Deformations of the hair cells in this manner produce neural impulses that are sent to the brain.
hallucinations					Sensory experiences that occur in the absence of external stimulation of the corresponding sensory organ.
health psychology					The branch of psychology dealing with the promotion and maintenance of sound health practices; studies relationship between health and behavior and mental processes.
heritability					The amount of variability in a trait due to genetic factors in a given population at a given time.
hertz (Hz)					The unit of measurement for studying a sound wave's frequency and pitch.
heterosexuality					Sexual attraction to individuals of the opposite sex.
heuristics					Strategies for solving problems that use simple and informal rules of thumb or general guidelines.
hippocampus [Plural, hippocampi]					The structure in the limbic system of the brain that plays a crucial role in memory.
homeostasis					The tendency for all animals to strive to maintain internal bodily states at a constant level.
homosexuality					Sexual attraction to individuals of the same sex.
hormones					Chemical substances, such as adrenalin, that are secreted directly into the bloodstream by endocrine glands.
horopter					An imaginary surface in space. Objects that fall on this surface have no binocular disparity; that is, they fall on corresponding regions of the two retinas.
hue					The psychological dimension of color (what we call "blue," "green," etc.); determined by the wavelength of light.
humanistic approach					An approach to personality that emphasizes the positive, fulfilling elements of life that are uniquely human.
humanistic therapy					A form of therapy in which the aim is to provide the client with a greater understanding of his or her motivations and needs by focusing on the person's unique potential for growth and self-actualization.
Huntington's chorea					A genetic disorder caused by a dominant lethal gene in which a person experiences slow but progressive mental and physical deterioration.
hyperopia					(Also called farsightedness.) A visual disorder in which the distance between the lens and retina is shorter than normal, causing light to be focused behind the retina. Farsighted people can see distant objects clearly, but close objects appear fuzzy.
hyperpolarization					The state that occurs after repolarization of the neuron when the inside of the axon actually becomes even more negative than it was during the resting potential.
hypochondriasis					A persistent and excessive worry of developing a serious illness or disease. People with this disorder often misinterpret normal physical aches and pains.
hypothalamus					The structure in the limbic system of the brain located directly below the thalamus. Different parts of the hypothalamus are involved in the control of hunger, thirst, body temperature, and sexual arousal. It is also linked to emotion.
hypothesis					A proposed relationship between two or more variables that can be tested empirically.
Hz					Abbreviation of hertz.
					I
id					According to Freud, the personality structure that is the unconscious reservoir of libido, or the psychic energy that fuels our inherited biological instincts.
illusions					Misperceptions of real objects or events.
immune system					A network of organs and cells that protect the body from invading bacteria, viruses, and other foreign substances.
imprinting					How some animals form attachments in the critical period shortly after their birth.
incentive theory					The theory that external events, such as goals or incentives, motivate or "pull'' us to behave.
inclusive fitness					The reproductive success of all those who share common genes.
incongruence					A discrepancy between a client's real and ideal perceptions of self.
incubation					An unconscious process by which the development of insight into a problem occurs after a person has stopped consciously thinking about potential solutions.
independent variable					The variable that is manipulated in an experiment. In psychological research, the independent variable is always a variable hypothesized to influence behavior.
inferential statistics					The kind of statistical analyses that allow the researcher to make informed estimates about characteristics of the complete population from the values of statistics computed from a single sample of data.
information processing					The way that knowledge is taken in and interpreted.
informed consent					A written statement provided to potential subjects by the researcher that discloses those aspects of the research that might affect their willingness to participate in the study. Constitutes a contract between subject and researcher.
insecure attachment					A kind of attachment in which an infant is reluctant to explore a new environment and is likely to cling to the caregiver in the presence of strangers.
insight					The sudden flash of understanding, where all of the pieces of a problem suddenly fit together and the solution becomes clear.
instinct					A genetically determined pattern of behavior that is shared by all members of the species.
instinct theory					The view, popular at the turn of the century, that all behavior is motivated by instinct—innate or genetically determined tendencies to perform certain acts or respond in particular ways.
instrumental conditioning					See operant conditioning.
intelligence					The capacity to acquire knowledge and to use that knowledge to solve problems.
intelligence quotient					See IQ.
intermittent reinforcement schedules					Reinforcement schedules in which responses are only occasionally reinforced.
interneurons					Neurons found only in the brain and spinal cord that allow for internal communication, receiving nerve impulses from sensory neurons and conveying these impulses to motor neurons.
interposition					The monocular depth cue produced when one object partially blocks our view of another object, causing the first object to appear closer.
intervening variable					Any hypothetical, organismic variable believed to cause behavior.
interview					A self-report procedure in which the researcher requires subjects to respond verbally to questions. The researcher then records the subjects' answers either in written form or on video or audio tape.
intrinsic motivation					Internally motivated; driven by a need for competence and self-determination.
introspection					The method used by structuralists for the self-analysis of a person's conscious experiences. Involves learning precise descriptions for sensations, images, and emotions caused by simple stimuli such as lights and sound.
introvert					Person who directs thoughts, feelings, and experiences inward.
ion					Any atom or molecule that has either a positive or negative electrical charge.
ion channel					A protein that is in the membrane of a cell that allows a particular ion to enter or leave the cell when open. It can also close.
IQ					The intelligence quotient; calculated by dividing a person's mental age by his or her chronological age, and then multiplying by 100.
iris					A small muscle that contracts or relaxes in response to the amount of light passing through the cornea.
					J
James-Lange theory					The theory proposing that physiological arousal precedes the experiencing of an emotion.
just noticeable difference (jnd)					The exact point at which an observer can recognize two stimuli as being different 50 percent of the time. The jnd is the unit of measurement for studying difference thresholds.
just world phenomenon					The tendency to believe that people generally get what they deserve and deserve what they get.
					K
kin selection					A type of selection process that favors altruistic acts aimed at individuals who share some of the altruist's genes.
kinesthetic system					Our sense of the location, movement, and posture of the skeletal joints and muscles.
					L
L-Dopa					A molecule from which the neurotransmitter dopamine is produced.
language					A written or spoken system of symbol manipulation that is used to represent and communicate our thoughts to others, and stories and information from generation to generation.
latency stage					Freud's fourth psychosexual stage (from about 5 or 6 years to puberty). During this stage, there are no unconscious conflicts.
latent content					According to Freud, the hidden meaning or underlying significance of a dream.
lateral hypothalamus					The brain region believed to function as the "on switch'' for feeding, because when stimulated chemically or electrically, it induces foraging and eating.
law of effect					Thorndike's description of operant conditioning: The effects that behavior has on the environment determine whether or not that behavior is likely to be repeated. Responses with positive effects tend to be repeated; those with negative effects tend not to be repeated.
law of parsimony					Those explanations that involve the fewest assumptions are to be preferred.
learning					A relatively permanent change in behavior based on experience.
lens					A transparent structure within the eye that changes shape depending on whether we are viewing objects close up or far away, permitting light to be focused on the retina.
lesion					A cut produced with pinpoint accuracy by surgically removing or severing tissue or by chemically or electrically destroying tissue.
levels of processing model					A model of memory based on the work of Craik and Lockhart, which holds that memory is information processing that occurs at many levels. This model proposes that memory has a boundless capacity and that it can hold information indefinitely.
LH					Abbreviation of luteinizing hormone.
life-span developmental psychology					The study of the processes and patterns of change that occur within individuals over the life span.
light adaptation					The process of our eyes adapting to increasing levels of illumination.
limbic system					A group of neural structures in the brain, including the amygdala, the hypothalamus, and the hippocampus, which are involved primarily with motivation, emotion, and memory.
linear perspective					The monocular depth cue produced by receding parallel lines, which gives the appearance that the lines converge on a vanishing point somewhere in the distance, creating the perception of depth.
linear profile					A graphical display of the scores from all of the subtests of a test to facilitate comparison among them, with adjacent scores connected with straight lines.
locus coeruleus					The part of the hind brain where over half of all of the neurotransmitter norepinephrine is located; it is involved in waking us up (arousal).
locus of control					People's expectancies regarding the source of control of their reinforcements. People who expect to control their own fate have an internal locus of control, whereas those who view their lives as being controlled by forces outside of their control have an external locus of control.
long-term memory					Our memory storehouse; believed to be unlimited in capacity.
longitudinal approach					A research design involving repeated observation or testing of the same group of people over an extended period of time.
loudness					The psychological dimension of a sound; determined by its amplitude. The more intense the vibration, the greater the amplitude, and the louder the psychological experience of the sound.
low-balling technique					A compliance technique in which a very attractive offer is made, but is then withdrawn after compliance with the original offer has occurred.
luteinizing hormone (LH)					In males, LH stimulates production of testosterone by the testes and in females, LH stimulates ovulation.
Lysergic Acid Diethylamide (LSD)					An hallucinogen or psychedelic drug that causes changes in perceptions and can produce severe thought disorders.
					M
magnitude estimation					A psychophysical method for collecting data where subjects are asked to assign a number proportional to some aspect of a stimulus, such as the brightness of a light.
maintenance rehearsal					The rote repetition of a given memory strategy, perhaps just by repeating a given item over and over again.
major depression					When a person experiences a deeply depressed mood (intense feelings of sadness) for two weeks or more, and also a loss of energy and motivation, a loss of interest in formerly pleasurable activities, sleep disturbances, and appetite disturbances. Often referred to as major depressive episodes.
mania					When a person experiences a strikingly elevated mood (intense feelings of happiness, optimism, and enthusiasm) for several days or more, usually accompanied by a powerful urge to talk (fast and loud), a whirlwind of restless and reckless behavior, thoughts that jump from one idea to the next, and a decreased need for sleep. Often referred to as manic episodes.
manifest content					According to Freud, what we remember of our dreams (as distinguished from the latent content, which he felt was key).
marital therapy					Therapy aimed at identifying and alleviating problems that have developed with a marital or other intimate partnership.
Maslow's hierarchy					Maslow's idea that our motivation for different activities passes through several hierarchical stages, with entrance to subsequent stages depending upon satisfying the needs in previous stages.
masochism					Obtaining gratification—often sexual—by suffering real or imagined physical pain or psychological distress.
mass to specific principle					The idea that control over large groups of muscles that are used in gross body movements develops faster than control over smaller groups of muscles that are used in finer movements.
Masters and Johnson model					The theory that vasocongestion and myotonia are the primary processes involved in the four stages of sexual arousal: excitement, plateau, orgasm, and resolution.
mean					The measure of central tendency that is the average score of a distribution of scores; calculated by adding all the scores and dividing that total by the number of scores.
median					The measure of central tendency that is the middle score—half of the scores fall below it and half fall above it.
medulla					A structure positioned at the very bottom of the brain that is involved with the control of autonomic processes such as breathing, swallowing, digestion, and heartbeat.
memory					The cognitive processes of encoding, storing, and retrieving information. Any learning that persists over time.
menarche					A girl's first menstrual period.
menopause					The cessation of the menstrual cycle.
mental age					The age level of the normative performance on an intelligence test that a child is able to match.
mental model					An internal representation of the external world—a set of beliefs about the relationships among phenomena. These personal views reflect and direct how we interact with the people and "things" around us.
mere exposure effect					Positive attitude development based on continued or repeated presentation to something.
meritocracy					A society in which each person is rewarded according to his or her merit.
metacognition					Self-awareness of one's cognitive processes.
MetaSearch					MetaSearch engines combine many individual search engines together for the most powerful search tool. For example, Metacrawler combines Yahoo!, Infoseek, AltaVista, Excite, Webcrawler, and Lycos to preform searches. This type of search is great for finding useful sites quickly.
microsleep					A short period of time, between 10 seconds and a minute in length, during which the brain actually enters a sleep state, regardless of what the person is doing at the time.
misinformation effect					Developing a distorted memory by unwittingly combining misleading information with one's own memory of an event.
MMPI					(Minnesota Multiphasic Personality Inventory) An objective test originally designed to distinguish individuals with different psychological disturbances from normal individuals.
mnemonic devices					Special techniques or strategies consciously employed in an attempt to improve memory.
mode					The score in a distribution that occurs most often.
modeling					The observation of another person engaging in behavior and then imitation of that behavior.
monocular depth cues					Depth cues that require only one eye to be able to use the information about depth.
monozygotic twins					Identical twins. Monozygotic twins develop from a single fertilized ovum (egg), which has split into two genetically identical cells.
mood disorders					Significant shifts or disturbances in mood that affect normal perception, thinking, and behavior.
moral development					The development of a person's thoughts and actions regarding right and wrong.
morpheme					The smallest unit of meaning in language.
motion parallax					The monocular depth cue in which nearby objects appear to race by while distant objects appear to move slowly.
motion sickness					The nausea and dizziness caused by some kinds of stimulation of the vestibular system, such as that sometimes experienced by flying in turbulence or by being onboard a ship in rough waters.
motivation					The causes of behavior, particularly as they influence the initiation and cessation of behavior and the intensity or strength of behavior.
motor area					The region of the cerebral cortex located in the portion of the frontal lobe closest to the central fissure; controls voluntary movement by sending nerve impulses to skeletal muscles.
motor neuron					A neuron that transmits signals from the brain or spinal cord to the body's muscles and glands.
multiple intelligences theory					Gardner's theory of intelligence, which generalizes the concept of intelligence away from the traditional focus on IQ by including problem solving in a wide variety of domains such as music and interpersonal competence.
multiple personality disorder					See dissociative identity disorder.
mutation					An accidental alteration in the DNA code within a single gene.
myelin sheath					A fatty substance that insulates and protects the neuron and facilitates speedy transmission of the nerve impulse.
myopia					(Also called nearsightedness.) A visual disorder in which the distance between the lens and retina is longer than normal, causing light to be focused in front of the retina. People who are nearsighted can see close objects well, but distant objects appear fuzzy.
myotonia					Muscle contractions or twitches that can occur during sexual arousal.
					N
narcissistic personality disorder					A disorder characterized by an exaggerated public sense of self-worth and obsessions with success fantasies.
narcotics					Psychoactive drugs that produce analgesia or pain reduction.
nasal cavity					The hollow portion of each nostril.
natural language searches					A search strategy that uses ordinary English questions.
naturalistic observation					A type of research in which data are gathered by observing behavior as it occurs naturally—free from the influence of the observer.
nearsightedness					See myopia.
need for achievement					The motivation to meet or surpass performance standards or to accomplish difficult tasks.
need for affiliation					The motivation to form friendships and associations with others.
need for power					The motivation to be in control of events, resources, or other people, usually for one's own advantage.
negative correlation					An increase in the values of one variable are accompanied by a decrease in the values of a second variable.
negative punishment					A stimulus or event that is removed after a response that decreases the likelihood that this response will occur again.
negative reinforcer					Any stimulus (such as a particular behavior) that, when removed, reduced, or prevented following a response, increases the frequency of that response over time.
nerve hearing loss					Decreases in hearing ability resulting from damage to the neural structures involved in transmitting auditory information from the cochlea to the brain, including the hair cells, basilar membrane, and the auditory nerve.
neural transmission					See action potential.
neurons					The basic unit of the nervous system. Neurons relay information to and from the brain by chemical and electrical means. Also called nerve cells, they consist of the cell body, dendrites, and axon.
neurotransmitters					Chemical substances that traverse the synaptic gap between neurons. These messengers are released by a presynaptic neuron to bind with a postsynaptic neuron—thereby influencing whether it will fire.
nontraditional students					College students who do not fall into the 17-24 year-old category.
noradrenaline					See norepinephrine.
norepinephrine					(Also called noradrenaline.) A neurotransmitter that is involved in the regulation of mood. Decreases in norepinephrine are related to depression; increases in it are related to feelings of vigor and self-confidence.
norm of reciprocity					A social norm dictating that favors should be returned.
normal distribution					The mathematical name for a frequency distribution of scores that is sometimes called the "bell-shaped curve.''
norms					In psychological testing, the average levels of performance on a test by a particular group of people, such as experienced bus drivers, or all 7-year-olds.
					O
obedience					Compliance with a demand (as distinguished from a request).
obesity					A body weight 20 percent in excess of that considered average for a given height.
object permanence					A developmental milestone; the understanding that objects do not disappear when they are removed from sight.
objective tests					Tests for measuring personality that are similar in structure to the ones given in the classroom to test knowledge of different content areas: they may contain multiple choice or true-false items, although some allow examinees to indicate the extent to which they agree with an item.
observational learning					Learning by observing the consequences others experience as a result of their behavior.
observational research					Research in which the variables of interest are observed without attempting to influence the values of the variables or to intervene in any way.
obsession					An involuntary recurring thought, idea, or image.
obsessive-compulsive disorder					An anxiety disorder in which an individual is beset by recurrent, unwanted thoughts or ideas and compelling urges to engage in repetitive, ritual-like behavior.
occipital lobe					One of four regions in the brain; this part lies at the back of the head and contains the visual processing areas.
olfactory bulb					An enlarged bundle of neural tissue, located in the brain just above the bone separating the brain from the olfactory mucosa, that sends neural information about smell to various regions of the brain.
olfactory mucosa					The part of the nose, located at the top of the nasal cavity just beneath the base of the brain, that contains odor receptors.
operant (or instrumental) conditioning					A form of learning in which behavior is affected by the consequences it produces.
operant chamber					An apparatus in which an animal's operant behavior can be easily observed, manipulated, and automatically recorded.
opiates					A class of highly addictive drugs that mimic endorphins in the brain. They tend to elevate mood and suppress pain.
opponent-process theory					In vision, Hering's theory that there are three sets of color-sensitive receptors in the visual system: one set for red and green, another for blue and yellow, and the third for black and white. Members of each set work in opposition to the other through neural inhibition. In motivation and emotion, Solomon's theory that for every emotional experience there is an opposite emotional experience that maintains our emotional and motivational levels at some homeostatic level.
optic nerve					The bundle of nerve fibers (the axons of ganglion cells) that make up the pathway leading from the retina to structures in the brain. Neural impulses laden with visual information travel this route.
optimal-arousal theory					The view that an organism's behavior is motivated by the need to maintain an optimal level of arousal.
oral stage					Freud's first psychosexual stage (the first 18 months of life). During this period, the mouth is the active erogenous zone, and the id impels the infant to use his or her mouth not only for eating and drinking, but for exploration as well.
orgasmic dysfunction					The inability to have an orgasm.
ossicles					Three bones (the malleus, incus, and stapes) in the middle ear that amplify and transmit the vibrations of the tympanic membrane to the oval window.
oval window					The membrane dividing the inner and middle ears which vibrates when stimulated by the ossicles.
ovum stage					The first of the three stages of prenatal development during which the zygote divides many times and the internal organs begin to form.
					P
pacinian corpuscle					A nerve ending that responds to touch and vibration.
pain threshold					The lowest level of stimulation at which pain is sensed.
papillae					The tiny bumps on the tongue that are lined with taste buds.
paranoid personality disorder					A disorder characterized by an exaggerated and unwarranted mistrust and suspicion of others. These symptoms are extremely rigid and unchangeable, even in the face of disconfirming evidence.
paranoid schizophrenia					A type of schizophrenia characterized primarily by systematic, well-developed, and persistent delusions. In particular, these delusions follow themes of either persecution or grandeur.
paraphilias					Sexual disorders in which stimulation from unusual objects or events results in sexual pleasure.
parasympathetic division					See parasympathetic nervous system.
parasympathetic nervous system					The part of the autonomic nervous system that functions to calm the body after stressful emergency situations are over.
Parkinson's disease					A progressive neurological disorder associated with decreased dopamine production in the substantia nigra, often characterized by rigidity in posture, difficulty in walking, or tremors involving the limbs or face.
paternity certainty					Assurance that a given male is, indeed, the father of a particular offspring.
Pavlovian conditioning					See classical conditioning.
perception					The processes by which the brain organizes and interprets sensations.
perceptual constancy					Our ability to perceive objects as possessing certain stable features, including lightness, size, and shape, despite changes in the condition under which we view those objects.
perceptual grouping					An organizational principle of Gestalt psychology that describes our ability to organize a figure into a meaningful pattern or shape.
performance (nonverbal intelligence)					The capacity for solving problems that does not depend on understanding language, but rather emphasizes behavior patterns such as putting together a puzzle.
peripheral nervous system					The network of sensory and motor neurons that connect the central nervous system to other parts of the body. Has two subsystems: the autonomic and somatic nervous systems.
permissive parents					Those who establish few rules and who do little to influence the behavior of their children.
person-centered therapy					A form of therapy in which the client is allowed to decide what to talk about without direction and judgment from the therapist.
personal fable					The belief that what one thinks and feels is completely new and unique and never before experienced by anyone else.
personality					A particular pattern of behavior prevailing across time and situations that differentiates one individual from another.
personality disorders					A class of disorders characterized by extremely rigid personality traits that impair functioning in personal, social, and occupational settings.
personality tests					Tests designed to reveal the components of an individual's personality, how one or more of the components interact with the other components, and how one person's personality differs from another's.
phallic stage					Freud's third psychosexual stage (from about 3 to 4 years to between 5 and 6 years). During this stage, the primary erogenous zone is the genital area.
phenotype					The outward expression of an organism's genotype; an organism's physical appearance and behavior.
phenylketonuria (PKU)					A genetic disorder characterized by the inability to break down phenylalanine, an amino acid found in many high protein foods.
pheromones					Chemicals that are secreted externally and communicate information between conspecifics. The nature of the information varies among species and includes such things as sexual receptivity, individual recognition, territorial possession, and alarm warnings.
phobic disorder					The unrealistic, excessive fear of a specific class of stimuli.
phoneme					The smallest unit of sound in a language; for example, English has about 40 phonemes.
physical dependence					The phenomenon in which the neurons in the nervous system come to require a drug to function adequately. Without the drug, the individual will experience withdrawal symptoms, which may include trembling, perspiration, nausea, headaches, and depending on the drug, even death.
pictorial depth cues					A subset of depth cues that can be used in a static image, such as a painting, to indicate depth.
pinna					The visible part of the ear.
pitch					The psychological quality of sound, which is determined by wave frequency. High frequency sound waves are perceived as high pitched.
PKU					Abbreviation of phenylketonuria.
place theory					The theory proposed by von Helmholtz stating that the basilar membrane is composed of independent nerve fibers, each sensitive to a different sound frequency, and so also sensitive to pitch.
placebo					In research, a completely inert substance or condition that may have an effect on subjects, because it is administered just as the active agent or condition is, and so the subjects believe it is affecting them.
pleasure principle					According to Freud, the rule that the id obeys: obtain immediate gratification, whatever form it may take.
pons					A structure just above the medulla that is involved with arousal and dreaming.
population					A large group of individuals to which researchers generalize their results.
positive punishment					A stimulus or event that is presented after a response that decreases the likelihood that this response will occur again.
positive reinforcer					Any stimulus (such as a behavior), that when it follows a response, increases the frequency of that response over time.
postconventional level					The last level of moral development in Kohlberg's theory. This level is concerned mainly with the development of personal values of morality.
postsynaptic neuron					During an action potential, the neuron that has receptors for the neurotransmitters that are released by the presynaptic neuron.
post-traumatic stress disorder (PTSD)					An anxiety disorder caused by experiencing a traumatic event or series of events. The individual experiences feelings of social withdrawal accompanied by atypically low levels of emotion toward routine events. In many cases, sufferers may reexperience, through dreams and flashbacks, the feelings of terror and shock experienced during the actual catastrophe.
preconventional level					The first level in Kohlberg's theory of moral development during which children tend to think solely in terms of the immediate consequences of their behavior.
prediction					The ability to foretell the value of one variable from the value of another variable.
predictive validity					A measure has predictive validity when it can be used to make predictions about future traits. For example, a measure of shyness that can be used to predict how shy an individual will be at some time in the future has predictive validity.
prejudice					A negative evaluation of an individual based on his or her membership in a particular group rather than the individual's actual characteristics.
prenatal period					The nine months between conception and birth.
preoperational period					The second of Piaget's four stages, which represents a 4- to 5-year period of transition (from age 2 to about 6 or 7) between first being able to think symbolically and being able to think logically.
presynaptic neuron					During an action potential, the neuron that releases the neurotransmitters into the synaptic cleft. The axon terminal is part of the presynaptic neuron.
preventive psychology					Any attempt to forestall the development of psychological problems by altering the sociocultural variables predictive of psychological distress.
primacy effect					In social psychology, the tendency to form impressions about people based on the first information we receive. In memory, the tendency to remember the first items in a list better than the items in the middle.
primary drives					Drives that arise from physiological needs and do not involve learning. Primary drives serve as the motivations that impel us to seek food when hungry, to drink when thirsty, and to seek warmth when cold.
proactive interference					The kind of interference in recall that is caused when previously learned information disrupts our ability to remember newer information.
procedural memory					The portion of long-term memory where our knowledge of simple, learned associations and our knowledge of how to perform well-learned habits is stored.
projection					According to Freud, a defense mechanism in which one's own unacceptable behaviors or thoughts are attributed to someone else.
projective tests					Unstructured personality measures in which a person is shown a series of ambiguous stimuli such as pictures, inkblots, or incomplete drawings. The person is asked to describe what he or she "sees'' in each stimulus or to create stories that reflect the theme of the drawing or picture. Responses are interpreted as reflecting certain personality characteristics.
prototypes					A set of characteristics that apply to the most representative or typical member of a category but not necessarily to all instances.
proximal stimuli					Stimuli that impinge directly on our sense receptors.
proximate causes					Events and conditions in the immediate environment that affect behavior.
proximity					A principle of perceptual grouping in which objects near one another tend to be perceived as a group.
proximodistal principle					The idea that development of the internal organs and torso occurs faster than development of the hands and feet.
psychedelics					Psychoactive drugs that produce dramatic changes in consciousness including hallucinations and enhanced perception.
psychiatrist					A medical doctor with training in the treatment of psychological disorders. Can prescribe drugs.
psychoactive drugs					Chemical substances that bring about a psychological effect, such as altering mood or perceptions.
psychoanalysis					The school of psychology founded by Freud. Portrays human behavior and personality development as due primarily to unconscious motivations and desires. Psychoanalysis is also a contemporary form of therapy aimed at providing the client insight into his or her unconscious motivations and impulses.
psychodynamic perspective					A view in psychology developed by Freud; focuses on the unconscious determinants of behavior and mental processes.
psychogenic amnesia					A dissociative disorder characterized by the inability to remember important events or vital personal information.
psychogenic fugue					A dissociative disorder involving amnesia which is also characterized by the individual leaving the area in which he or she lives, and then assuming a new identity in a new locale.
psychological dependence					An all-consuming craving to use a psychoactive drug for its euphoric effects.
psychological disorders					Atypical, maladaptive, disturbing, and unjustifiable patterns of behaving, thinking, and/or feeling.
psychology					The scientific study of behavior and cognitive processes.
psychometrics					The area of psychology that is devoted to psychological measurement.
psychophysics					The branch of perceptual studies that explores the relationship between the quantitative qualities of a stimulus and our psychological experience of that stimulus.
psychosexual stages					Freud's theory of developmental stages that are defined by the part of the body or erogenous zone from which sexual gratification is derived.
psychosurgery					Unalterable brain surgery designed to relieve the symptoms of psychological disorders.
psychotherapy					Any attempt to use known psychological principles to bring about improved emotional, cognitive, or social adjustment.
PTSD					Abbreviation of post-traumatic stress disorder.
puberty					Sexual maturation, accompanied by the ability to reproduce.
punisher					Any stimulus or event that, when it occurs following a response, decreases the frequency of that response. The delivery of a punisher following a response is called punishment.
pupil					The opening, surrounded by the iris, that allows light to enter the eye.
					Q
questionnaire					A self-report technique in which a series of written questions, specifically designed to address a particular topic, are given to a subject to answer.
					R
random assignment					An experimental procedure in which each subject is assigned to a group on the basis of chance alone.
rational emotive therapy (RET)					Therapy based on the belief that psychological problems are caused by how people think about upsetting events.
rationalization					According to Freud, a defense mechanism that justifies an unacceptable action with a more acceptable, but false, excuse.
reaction-formation					According to Freud, a defense mechanism that involves behaving in a manner that is the opposite of how one really feels because the true feelings produce anxiety.
reality principle					According to Freud, the rule used by the ego to satisfy the demands of the id realistically, yielding to and accounting for the demands of reality, sometimes delaying the gratification of desires springing forth from the id, and sometimes softening the rules and reasons offered by the superego.
reasoning					The process of drawing conclusions from a set of facts.
receptor sites					In the synapse, molecules on the surface of the postsynaptic neuron; where the neurotransmitters attach and either stimulate or inhibit the postsynaptic neuron's firing.
reciprocal determinism					The idea that behavior, environment, and personal variables, such as cognitions and perceptions, interact to determine personality.
reflection					The therapist's sensitive rephrasing or mirroring of the client's statements during therapy.
refractory period					In neural transmission, a very brief recovery period just after the neuron has stimulated another neuron, in which its membrane cannot be stimulated to generate another nerve impulse. In the sexual response, the recovery time after orgasm during which another orgasm cannot be achieved.
regression line					The line drawn through the points in a scatter plot that allows researchers to predict the value of one variable when given the value of the other variable.
reinforcer					An event that increases the frequency of the response it follows.
relational hypotheses					Hypotheses that specify that two or more variables are related, but none of the variables can be specified to cause the other variable(s).
relative size					The monocular depth cue in which large objects appear closer than small objects because they cast larger images on the retina.
reliability					A test is said to be reliable when it provides consistent results, as assessed by repeated testing, using alternate forms of the test, or splitting the test and comparing results from each half.
reliability coefficient					A numerical index of the reliability of an intelligence test (or any other type of psychological test) derived by computing a correlation coefficient for the examinees' scores from two different administrations of the same test.
REM sleep					The stage of sleep characterized by rapid eye movements and dreaming.
replication					In order to judge the strength of a study№s findings, it must be replicated, or repeated, using the same experimental design but a different set of participants. If the same results are achieved, then we can have a higher level of confidence in the original study.
repolarization					The second phase of an action potential when the inside of the axon returns to its negative voltage.
representativeness heuristic					Provides a problem-solving shortcut by quickly classifying an object into the category to which it appears to be the most similar.
repression					According to Freud, the mental force responsible for actively keeping an individual from consciously discovering their potentially threatening or anxiety-provoking memories.
research psychologist					A psychologist, generally a Ph.D., who conducts psychological research.
residual schizophrenia					The diagnosis for individuals who have experienced at least one episode of schizophrenia but who are currently not exhibiting major symptoms of the disorder.
resistance					In psychoanalysis, the mental forces that relegate memories of past events into unconsciousness. Also, resistance refers to a development during therapy in which the client becomes defensive, unconsciously attempting to halt further insight by censoring his or her true feelings.
respiration					(1) In aerobic organisms, the intake of oxygen and the liberation of carbon dioxide. (2) In cells, the oxygen-requiring stage in the breakdown and release of energy from fuel molecules.
response bias					The tendency of an individual to adopt a set response regardless of what question is being asked.
response criterion					In a signal detection experiment, the level of sensation above which an individual will report detecting a stimulus and below which he or she will report not detecting a stimulus.
resting potential					The electrical potential (–70 millivolts) of the neuron when it is not generating a nerve impulse.
RET					Abbreviation of rational emotive therapy.
reticular formation					A fingerlike network of neurons that extends from the lower tip of the medulla through the thalamus and that plays a role in sleep and arousal.
retina					The thin layer of receptors, the rods and cones, that lines the interior of the back of the eye.
retinal disparity					Also called binocular disparity. This is the difference between the visual input from each of our eyes. Because we have two eyes that are slightly spaced apart on our faces, we get a slightly different view of the world from each. This helps us to see depth.
retrieval					The active process of locating and using stored information.
retroactive interference					The kind of interference in recall that is caused when recently learned information disrupts our ability to remember older information.
retrograde amnesia					Loss of the ability to remember events that occur prior to a brain injury.
reuptake					The process by which the sending neuron absorbs the excess neurotransmitters that have been left in the synapse after the action potential occurs.
rods					Light-sensitive receptors that are found throughout the retina except in the fovea.
Rorschach inkblot test					A projective test in which the examinee is shown a series of symmetrical inkblots and then is asked to describe what he or she thinks they represent. Responses are interpreted as reflecting certain personality characteristics.
					S
sadism					Obtaining gratification, often sexual, from inflicting real or imagined physical pain and psychological distress on others.
sample					A representative subset of a population.
saturation					The purity of a color, which is determined by intensity of wavelength.
scatter plot					A two-dimensional graph of plotted data points used to display the degree of correlation between two variables.
Schachter's two-factor theory of emotion					The theory that two factors are involved in emotion: physiological arousal and cognition.
schema					An overall framework for processing information about people, objects, or situations. A mental representation of the world based on previous experiences.
schizophrenia					A general term for a group of psychological disorders involving distortions of thought, perception, and emotion, bizarre behavior, and social withdrawal.
secondary drives					Drives that are brought about through experience. They are learned drives believed to underlie psychological motives such as acquiring wealth, desiring affiliation, seeking approval from parents and significant others, and so on.
secondary reinforcers					Stimuli and events that acquire their reinforcing properties through their association with primary reinforcers.
secure attachment					A kind of attachment in which infants will use their caregiver as a "base'' for exploring a new environment. They will venture out from the caregiver to explore a strange situation but return periodically.
selective attention					Focusing conscious attention on only one part of the stimulus field, as in the "cocktail party effect."
selective breeding					A procedure in which animals are deliberately mated to produce offspring that possess particular desirable characteristics.
self-actualization					According to Rogers, our need to strive to achieve our greatest potential as human beings.
self-concept					One's opinion of one's self. According to Rogers, our self-concept is affected by the way we are evaluated and treated by others.
self-efficacy					Bandura's notion that a person's expectations of success are a primary influence in determining whether that person will attempt to change his or her environment.
self-perception theory					A theory claiming that we come to understand our own attitudes by observing our own behavior.
self-report					A technique in which people provide subjective information about themselves—feelings, beliefs, evaluations, or interests—to the researcher.
semantic memory					A type of memory found in long-term storage that houses data, facts, and other information, including vocabulary.
semicircular canals					The structures in the inner ear that contain receptors sensitive to changes in body orientation.
sensation					The process of receiving and representing basic information from our environment via our sense receptors.
sensitive period					See critical period.
sensitization					An increased response to a repeated stimulus.
sensorimotor period					Piaget's first stage of cognitive development, marked by an orderly progression of increasingly complex cognitive development: reflexive behavior, object permanence, a rough approximation of cause and effect, imitating the actions of others, and symbolic thinking. Lasts from birth to two years.
sensory neuron					A neuron that transmits nerve impulses from the sensory receptors to the brain and spinal cord.
sensory memory					A primitive form of memory where the physical features of a stimulus are stored for extremely brief durations.
separation anxiety					A set of fearful responses in infants, such as crying and clinging to their caregiver, when the caregiver attempts to leave the infant's presence.
serotonin					An inhibitory neurotransmitter found in the brain and spinal cord that plays an important role in the brain's control of sleep and arousal, body temperature, and sensory and perceptual functions.
serum cholesterol					A chemical that occurs naturally in all tissues and in the bloodstream, where it serves as a detoxifier. Serum cholesterol has two important forms: low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDL is often called bad cholesterol because high levels of it are associated with the formation of arteriosclerotic plaques, which clog arteries. HDL is sometimes referred to as good cholesterol because high levels are inversely associated with plaque build-up.
set point					The idea that the hypothalamus, functioning as a homeostatic mechanism, sets a level, probably based on the combination of body weight, blood sugar levels, and metabolism, that determines when and how much an animal will eat.
sex chromosomes					The chromosomes containing the instructional code for the development of male or female sex characteristics.
sexual dimorphism					A situation in which the two sexes of a species display distinct differences in physical traits such as size, coloration, and/or defensive structures.
sexual dysfunction					An impairment or difficulty in achieving sexual arousal and orgasm.
sexual selection					The evolution of characteristics that confer reproductive advantage to an organism while having no other value.
sexually transmitted diseases (STDs)					Diseases that are contracted through sexual contact with another person.
shaping					Reinforcing any behavior that successfully approximates the desired response until that response is acquired.
short-term memory					(Also called working memory.) This storage area has a limited capacity (around seven chunks of information) and limited duration (typically less than 20 seconds unless rehearsed).
sign stimuli					Stimuli that elicit fixed-action patterns.
signal detection theory					The theory that detection of any stimulus is a matter of distinguishing that stimulus from all other stimuli in the sensory world. Involves careful measurement of all the factors that lend to detection, false alarms, and missed detection. These factors include personal experience, expectations, motivation, and fatigue level.
similarity					A principle of perceptual grouping in which objects that look alike tend to be perceived as a group.
16PF					A personality inventory widely used among marriage and vocational counselors. The PF stands for personality factors, and the items test such factors as intelligence, sensitivity, shrewdness, and trust.
social clock					The culturally-prescribed timing for important social events, such as college attendance, marriage, and retirement.
social cognition					The processing of information about other people and social situations.
social facilitation					A change in task performance due to the presence of others.
social interest					According to Adler, an innate desire to make contributions to society.
social learning theory					The idea that both consequences of behavior and the individual's beliefs about those consequences determine personality and behavior.
social norms					Informal rules defining the expected and appropriate behavior in specific situations.
social perspective					A view in psychology emphasizing the role that our social environment plays in shaping our behavior, attitudes, and thinking.
social psychology					The branch of psychology that studies how thought, feeling, and behavior of individuals are influenced by the actual, imagined, or implied presence of others.
somatic nervous system					The part of the peripheral nervous system that controls the actions of the skeletal muscles.
somatoform disorders					An anxiety-based disorder involving a bodily or physical problem for which there is no physiological basis.
somatosensory areas					The region of the cerebral cortex lying in the parietal lobes just behind the central fissure that is involved in the ability to sense warmth, cold, pain, touch, and bodily movement.
somatosensory system					The system by which we sense pressure, temperature, pain, balance, and equilibrium.
sound wave					An alternating pattern of high and low air pressure caused by a vibrating object.
species-typical behavior					Behavior that is common among the members in a given species.
spontaneous recovery					The re-emergence of a response after it has been extinguished.
standard deviation					A descriptive statistic that expresses the amount of variability among scores in a frequency distribution.
standard score					The score that shows how far or how close a person's original responses are from the average level of responses on, for example, an intelligence test.
standardization					The process of establishing the norms of a test across hundreds or thousands of people in each group (age, sex, ethnicity) to which the test is later to be administered.
Stanford-Binet					The first widely used, individually administered English-language intelligence test.
state-dependent memory					The tendency to recall information better when the subject's mental or emotional state at retrieval matches that during encoding.
statistically significant					A term used in inferential statistics to indicate that results from a study are not due to chance but represent differences that can be generalized to an entire population of individuals.
STD					Abbreviation of sexually transmitted diseases.
stereotypes					Oversimplified schemata that are applied to entire groups of people.
stimulants					Psychoactive drugs that speed up the nervous system's activities, producing increases in arousal and mood.
stimulus					Any internal or external change or signal that influences the activity of an organism or of part of an organism.
storage					The process of maintaining information in memory for future use.
stranger anxiety					A set of fearful responses in infants, such as crying and clinging to their caregiver, in the presence of strangers.
stress					A pattern of physiological, behavioral, and cognitive responses to real or imagined environmental stimuli that are perceived as endangering or otherwise threatening to well-being or personal abilities.
stressors					Environmental stimuli that are perceived as endangering or otherwise threatening to well-being or personal abilities.
stroboscopic movement					A form of perceived movement that can be created by flashing a series of lights in rapid succession.
structuralism					The school of psychology (founded by Wilhelm Wundt) that emphasizes the structure of the mind as being the appropriate subject matter for psychology.
sublimation					According to Freud, redirecting pleasure-seeking or aggressive instincts toward socially acceptable goals.
substance abuse					Repeated use of alcohol or drugs that causes harm to physical health, interferes with fulfilling obligations at home, work, or school, and may lead to financial, legal and interpersonal problems.
substance dependence					A consistent serious and pronounced pattern of substance abuse. Physical dependence and tolerance are developed.
substantia nigra					The part of the brain that is important for controlling movement. For example, destruction of the cells of the substantia nigra cause the symptoms of Parkinson's Disease. Dopamine is the neurotransmitter used here.
superego					According to Freud, the repository of an individual's moral values that is stocked with laws, mores, and sanctions of the society in which one lives.
surface structure					The organization of a sentence in terms of its component phrases as it is actually spoken or read.
symbol					A mental construction that stands for or represents something else.
sympathetic division					See sympathetic nervous system.
sympathetic nervous system					The part of the autonomic nervous system that arouses the body in preparation for stressful or emergency situations.
synapse					The tiny gap between neurons across which communication occurs. A specialized junction between two neurons where the activity in one influences the activity in the other; in mammals, transmission across the synaptic gap is by means of chemical substances (neurotransmitters) and may be excitatory or inhibitory.
synaptic cleft					The tiny space between the pre-synaptic (sending) and post-synaptic (receiving) neurons, into which neurotransmitters are released during neurotransmission.
synaptic vesicles					Tiny, saclike structures found in the terminal buttons that contain neurotransmitters.
syntax					The well-defined rules that specify how the words of a sentence should be arranged.
systematic desensitization					A treatment for anxiety in which the client is trained to relax in the presence of increasingly fearful stimuli.
		T
tacit inference		Tacit Inferences are conclusions that people reach about the missing details of information about other people, or that resolve ambiguities about those details.
Tardive dyskinesia		An adverse side effect of many traditional antipsychotic drugs characterized by involuntary movements such as tics and other motor problems.
Taste		The sensation produced by chemical molecules stimulating receptor cells found in the mouth.
taste buds		The parts of the papillae in the mouth that house the receptors for taste.
TAT (thematic apperception test)		A projective test in which a person is first shown a series of ambiguous pictures that involve people. Then he or she is asked to make up a story about what the people are doing or thinking. These themes are believed to reflect the examinee's personality characteristics.
Telegraphic speech		A form of early speech in which a young child uses short, two-word phrases resembling those sent in a telegram.
Teratogen		Potentially damaging chemicals, viruses, or other agents that can pass from the mother to the embryo or fetus during prenatal development.
Terminal button		The part of the neuron that releases neurotransmitters.
test bias		The discounting or favoring of an individual's test performance due to the particular experiences of that individual. To the extent that the ability to answer test items correctly depends on previous learning, the intelligence test becomes less of a valid measure of capacity and more a measure of achievement.
Testimonial		An appeal designed to get the reader to believe that a conclusion is true when only the unsupported opinion of the speaker is given as evidence.
Texture gradient		The monocular depth cue in which objects that are larger and coarser appear closer than objects that are smaller and smoother.
Thalamus		The structure of the central core that relays sensory information to the cerebral cortex. A part of the vertebrate brain tucked below the cerebrum; the main relay center between the brainstem and the higher brain centers.
Thematic apperception test		See TAT.
Theory		A set of statements attempting to explain relationships that may exist between behavior and other variables.
theta rhythm		A brain wave pattern whose discovery supports a blend of physiological and psychological interpretations of dreaming, because theta rhythms have been observed in mammals while they are dreaming, AND while they are engaged in essential life-survival activities. See also the Scientific American article The Meaning of Dreams for further information.
Thinking		The manipulation or construction and modification of internal symbolic presentations.
Three-component model		The model of memory proposed by Atkinson and Shiffrin, which postulates a sensory register (or storage) that "picks up'' and briefly holds stimuli from the environment, a short-term storage of limited capacity, and a long-term storage where information is kept with some permanency.
Timbre		The psychological quality corresponding to a sound's clarity.
Token economy		A system for improving the behavior of severely impaired patients that involves tokens of some kind, which are later exchangeable for different goods and services, and are used to reinforce desired behavior.
Tolerance		A physical condition in which neurons in the central nervous system respond progressively less to a drug. Larger doses of the drug are required to produce the same effects on the nervous system that smaller doses produced earlier.
top-down processing		Processing of a pattern that begins with the higher brain centers directing receptors to attend to particular features of the pattern.
Traditional students		College students who fall in the 17-24 year-old category.
Trait		A relatively stable, measurable characteristic of a person.
Transduction		The conversion of physical energy, such as sound waves, into nerve impulses that can be interpreted by the brain.
Transference		The process by which a client begins to project powerful attitudes and emotions onto the therapist.
Treatment condition		The part of an experiment in which the independent variable is manipulated and its effect on the subject's behavior is measured.
Triarchic theory of intelligence		Sternberg's theory that generalizes intelligence testing and the study of intelligence beyond that of IQ tests by accounting for three different aspects of intelligence: the specific cognitive processes that underlie intelligent behavior, the way in which previous experience with a particular kind of problem affects the way that a problem is solved, and the environmental context within which the problem solving occurs.
trichromatic theory		The theory proposed by Young and Helmholtz that the typical human eye has color receptors sensitive to the primary colors of red, green, and blue.
tympanic membrane		(Also called ear drum.) A thin, conically shaped membrane separating the outer and middle ears that vibrates when struck by sound waves.
Type A		Set of behaviors characterized by competitive, hurried, intensely driven, ambitious, and anger-prone individuals.
Type B		Set of behaviors characterized by calm, easygoing, and unhurried individuals.
			U
unconditional positive regard			Love and acceptance with no strings attached. According to Rogers, unconditional positive regard is the key to promoting personal growth.
unconditioned response (UCR)			In classical conditioning, the response, such as salivation, that is naturally elicited by the unconditioned stimulus, such as food.
unconditioned stimulus (UCS)			In classical conditioning, any stimulus, such as food, that naturally elicits a reflexive response, such as salivation.
unconscious			The inaccessible part of the mind in Freud's theory; generally, anything that occurs outside conscious awareness.
undifferentiated schizophrenia			A type of schizophrenia whose symptoms do not fall neatly into any of the other categories of schizophrenia. Undifferentiated schizophrenia is characterized by fragments of various symptoms.
				V
validity				A test is said to be valid when it measures what it is supposed to measure.
validity coefficient				The correlation between the score on a test and some other variable of interest.
value				The level or degree of a variable.
variable				Any characteristic of organisms or the environment that may vary from one instance to the next.
variable-interval (VI) schedule				A reinforcement schedule in which the amount of time between reinforcement deliveries varies.
variable-ratio (VR) schedule				A reinforcement schedule in which the number of responses required for reinforcement varies from one reinforcer delivery to the next.
variance				A single number that represents the total amount of variation in a set of scores.
variation				The biological and psychological differences found across individuals of any given species.
vasocongestion				The flow of blood during arousal into the genital area.
ventromedial hypothalamus (VMH)				The brain region thought to be the "off switch'' for eating because, when stimulated, eating stops.
verbal intelligence				The problem-solving capacity for language-oriented problems such as reading comprehension and vocabulary.
vergence				A type of eye movement where the eyes move at the same time but in opposite directions; that is, they either rotate towards or away from each other. These eye movements are used to see nearer or farther objects, respectively.
vestibular sacs				A set of receptors located just below the semicircular canals; play a critical role in maintaining the head in its proper upright orientation.
vestibular system				Our sense of equilibrium or balance.
VI				Abbreviation of variable-interval schedule.
visual acuity				Keenness of vision. Visual acuity is greatest for images that are focused on the fovea.
VMH				Abbreviation of ventromedial hypothalamus.
volley principle				The idea that the hair cells in the cochlea alternately fire and rest. This principle was developed to account for hearing sound wave frequencies above 1000 Hz.
voyeurism				A sexual disorder involving obtaining sexual pleasure through visual means–by viewing sexual organs and sexual acts.
VR				Abbreviation of variable-ratio schedule.
		W
WAIS-R		The current version of Wechsler's individually administered adult intelligence test, called the Wechsler Adult Intelligence Scale, Revised.
wave frequency		The speed with which variations (from high to low) in air pressure occur.
wavelength		The distance from one wave crest to the next. Different wavelengths of light, for example, are seen as distinct hues or colors.
Weber's law		States that a stimulus needs to charge by a certain proportion for that charge to be noticed.
Wernicke's area		The portion of the temporal lobe that is involved in the motor production of speech.
WISC-R		The current version of Wechsler's individually administered intelligence test for children, called the Wechsler Intelligence Scale for Children, Revised.
withdrawal		Behavioral, cognitive, and physiological changes occurring when heavy and prolonged substance use is discontinued.
working memory		See short-term memory.
	X
XYY syndrome	A genetic disorder in which an individual has an extra Y chromosome.
	Y
Yerkes-Dodson law	The inverted U-shaped relationship between performance and arousal: for any task to be performed there is an optimal level of arousal necessary for best performance. Too little or too much arousal interferes with performance.
	Z
zygote	Term used for the egg for the two weeks following fertilization in this first stage of prenatal development.