Glossary of Terms
Psychology Key Terms

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absolute threshold The minimum amount of stimulus energy that can be detected 50 percent of the time-

accessory structures Structures- such as the outer part of the ear- that modify a stimulus-

accommodation (in cognitive development) The process of modifying schemas as an infant tries out familiar schemas on objects that do not fit them-

accommodation (in eye structure) The ability of the lens to change its shape and bend light rays so that objects are in focus-

acoustic codes Mental representations of stimuli as sounds-

action potential The electrochemical impulse or message that is sent down an axon and stimulates release of a neurotransmitter-

actor-observer bias The tendency to attribute other people’s behavior to internal causes while attributing one’s own behavior to external causes-

actualizing tendency An innate inclination toward growth and fulfillment that motivates all human behavior-

adaptation Decreasing responsiveness to an unchanging stimulus-

addiction Development of a physical need for a psychoactive drug-

aggression An act that is intended to harm another person-

agonists Drugs that bind to a receptor and mimic the effects of the neurotransmitter that normally fits that receptor-

agoraphobia A strong fear of being alone or away from the safety of home-

alcoholism A pattern of continuous or intermittent drinking that may lead to addiction and almost always causes severe social- physical- and other problems-

algorithms Systematic procedures that cannot fail to produce a correct solution to a problem-

altered state of consciousness A condition that exists when changes in mental processes are extensive enough to produce noticeable differences in psychological and behavioral functioning-

altruism An unselfish concern with another’s welfare-

amplitude The distance between the peak and the baseline of a wave-

amygdala A forebrain structure that links information from various systems and plays a role in emotions-

anal stage The second of Freud’s psychosexual stages- occurring during the second year of life- in which the focus of pleasure shifts from the mouth to the anus-

analgesia Reduction in the sensation of pain in the presence of a normally painful stimulus-

anchoring heuristic A shortcut in the thought process that involves adding new information to existing information to reach a judgment-

androgens Masculine hormones that circulate in the bloodstream-

anorexia nervosa An eating disorder characterized by self-starvation and dramatic weight loss

antagonists Drugs that bind to a receptor and prevent the normal neurotransmitter from binding-

anterograde amnesia A loss of memory for events that occur after a brain injury-

antidepressants Drugs that reduce depression-

antisocial personality disorder A long-term- persistent pattern of impulsive- selfish- unscrupulous- even criminal behavior-

anxiety disorder A condition in which intense feelings of fear and dread are long-standing or disruptive-

anxiolytics Drugs that reduce tension and symptoms of anxiety-

arousal A general level of activation reflected in several physiological systems-

arousal theory A theory stating that people are motivated to maintain what is- for them- an optimal level of arousal-

arousal:cost-reward theory A theory that attributes helping behavior to people’s efforts to reduce the unpleasant arousal they feel when confronted with a suffering victim- while also considering the costs involved-

artificial intelligence (AI) The field that studies how to program computers to imitate the products of human perception- understanding- and thought-

assertiveness training A set of methods for helping clients learn to express their feelings and stand up for their rights in social situations-

assessment center An extensive set of exercises designed to determine an individual’s suitability for a particular job-

assimilation The process of taking in new information about objects by using existing schemas on objects that fit those schemas-

association cortex The parts of the cerebral cortex that integrate sensory and motor information and perform complex cognitive tasks-

attachment A deep- affectionate- close- and enduring relationship with a person with whom a baby has shared many experiences-

attention The process of directing and focusing certain psychological resources to enhance perception-

attitude A tendency toward a particular cognitive- emotional- or behavioral reaction to objects in one’s environment-

attribution The process of explaining the causes of people’s behavior- including our own-

auditory nerve The bundle of axons that carries messages from the hair cells of the cochlea to the brain-

authoritarian parents Parents who are firm- punitive- and unsympathetic-

authoritative parents Parents who reason with their children and are firm but understanding-

autonomic nervous system The subsystem of the peripheral nervous system that carries messages between the central nervous system and the heart- lungs- and other organs and glands in the body-

autonomous work teams (AWTs) Self-managed employee groups that do not report to anyone for routine daily supervision-

availability heuristic A mental shortcut through which judgments are based on information that is most easily brought to mind-

aversive conditioning A method for reducing unwanted behaviors by using classical conditioning principles to create a negative response to some stimulus-

avoidance conditioning The process of learning particular responses that avoid an aversive stimulus-

axon A fiber that carries signals away from the cell body-






babblings Repetitions of syllables; the first sounds infants make that resemble speech-

basilar membrane The floor of the fluid-filled duct that runs through the cochlea-

behavior modification Treatments that use operant conditioning methods to change behavior-

behavior therapy Treatments that use classical conditioning principles to change behavior-

behavioral approach A view based on the assumption that human behavior is determined mainly by what a person has learned in life- especially by rewards and punishments-

behavioral genetics The study of the effect of genes on behavior-

biased sample A group of research participants selected from a population each of whose members did not have an equal chance of being chosen for study-

big-five model A view based on factor-analytic studies suggesting the existence of five basic components of human personality: neuroticism- extraversion- openness- agreeableness- and conscientiousness- Also called the five-factor model-

binocular disparity A depth cue based on the difference between the retinal images received by each eye-

biological approach The view that behavior is the result of physical proc­esses- especially those relating to the brain- to hormones- and to other chemicals-

biological psychologists Psychologists who analyze the biological factors influencing behavior and mental processes-

biological psychology The study of physical and chemical changes involved in behavior and mental processes-

biopsychosocial model Explaining mental disorders as the combined result of biological- psychological- and sociocultural factors-

bipolar disorder A condition in which a person alternates between the two emotional extremes of depression and mania-

bisexual Referring to sexual desire or behavior that is focused on members of both sexes-

blind spot The point at which the optic nerve exits the eyeball-

blood-brain barrier A feature of blood vessels in the brain that prevents some substances from entering brain tissue-

bottom-up processing Aspects of recognition that depend first on information about stimuli that come up to the brain from the sensory systems-

brightness The overall intensity of the wavelengths making up light-

Brown-Peterson procedure A method for determining how long unrehearsed information remains in short-term memory-

bulimia nervosa An eating disorder that involves eating massive quantities of food and then eliminating the food by self-induced vomiting or laxatives-

burnout A pattern of physical and psychological dysfunctions in response to continuous stressors-

bystander effect A phenomenon in which the chances that someone will help in an emergency decrease as the number of people present increases-






case studies Research involving the intensive examination of some phenomenon in a particular individual- group- or situation-

central nervous system (CNS) The brain and spinal cord-

cerebellum The part of the hindbrain that controls finely coordinated movements-

cerebral cortex The outer surface of the forebrain-

chromosomes Long- thin structures in every biological cell that contain genetic information in the form of genes-

chunks Stimuli that are perceived as units or meaningful groupings of information-

circadian rhythm A cycle- such as waking and sleeping- that repeats about once a day-

classical conditioning A procedure in which a neutral stimulus is paired with a stimulus that elicits a reflexive response until the neutral stimulus alone comes to elicit a similar response-

client-centered therapy A type of therapy in which the client decides what to talk about and when- without direction- judgment- or interpretation from the therapist- Also called person-centered therapy-

clinical and counseling psychologists Psychologists who seek to assess- understand- and modify abnormal behavior-

cochlea A fluid-filled spiral structure in the inner ear in which auditory transduction occurs-

coding Translation of the physical properties of a stimulus into a specific pattern of neural activity-

cognitive approach A view that emphasizes research on how the brain takes in information- creates perceptions- forms and retrieves memories- processes information- and generates integrated patterns of action-

cognitive dissonance theory A theory stating that uneasiness results when people’s thoughts- beliefs- and attitudes are inconsistent with one another and with their behavior- and that such uneasiness motivates people to try to restore consistency-

cognitive map A mental representation of the environment-

cognitive psychologists Psychologists whose research focus is analysis of the mental processes underlying judgment- decision making- problem solving- imagining- and other aspects of human thought or cognition-

cognitive therapy An organized problem-solving approach in which the therapist actively collaborates with clients to help them notice how certain negative thoughts precede anxiety and depression-

cognitive-behavior therapy Behavioral treatment methods that help clients change the way they think- as well as the way they behave-

community psychologists Psychologists who work to obtain psychological services for underserved client groups- and to prevent psychological disorders by working for changes in social systems-

community psychology A mental health approach whose goal is to minimize or prevent psychological disorders by promoting social change and making treatment methods more accessible to those who normally have little or no access to psychological services-

competition Any type of behavior in which individuals try to attain a goal for themselves while denying that goal to others-

compliance The adjustment of one’s behavior because of a direct request-

concepts Categories of objects- events- or ideas that have common properties-

concrete operations According to Piaget- the third stage of cognitive development- during which children can learn to count- measure- add- and subtract-

conditioned response (CR) The response elicited by the conditioned stimulus-

conditioned stimulus (CS) An originally neutral stimulus that now elicits a conditioned response-

conditions of worth According to Rogers- circumstances in which an individual experiences positive regard from others only when displaying certain behaviors or attitudes-

cones Photoreceptors in the retina that are less light-sensitive than rods- but that can distinguish colors-

confirmation bias The tendency to pay more attention to evidence in support of one’s hypothesis about a problem than to evidence that refutes that hypothesis-

conflict What occurs when a person or group believes that another person or group interferes with the attainment of a goal-

conformity The changing of one’s behavior or beliefs to match those of others- generally as a result of real or imagined- though unspoken- group pressure-

confounding variable Any factor that affects the dependent variable along with- or instead of- the independent variable-

congruence In client-centered therapy- a consistency between the way therapists feel and the way they act toward the client-

conscious level The level of consciousness at which mental activities accessible to awareness occur-

consciousness The awareness of external stimuli and our own mental activity-

conservation The ability to recognize that the important properties of a substance- such as number- volume- or weight- remain constant despite changes in shape- length- or position-

contact hypothesis The idea that stereotypes and prejudice toward a group will diminish as contact with the group increases-

context-dependent memories Memories that are helped or hindered by similarities or differences between the contexts in which they are learned and recalled-

control group The group that receives no treatment or provides some other baseline against which to compare the performance or response of the experimental group-

conventional Referring to moral reasoning that reflects a concern about other people- as well as the belief that morality consists of following rules and conventions-

convergence A depth cue resulting when the eyes rotate to project the image of an object on each retina-

convergent thinking The ability to apply the rules of logic and what one knows about the world to narrow down the possible solutions to a problem-

conversion disorder A somatoform disorder in which a person appears to be- but actually is not- blind- deaf- paralyzed- or insensitive to pain in various parts of the body-

cooperation Any type of behavior in which several people work together to attain a goal-

cornea The curved- transparent- protective layer through which light rays enter the eye-

corpus callosum A massive bundle of fibers that connects the left and right cerebral hemispheres-

correlation The degree to which one variable is related to another-

couples therapy A form of therapy that focuses on improving communication between partners-

creativity The capacity to produce original solutions or novel compositions-

critical period An interval during which certain kinds of growth must occur if development is to proceed normally-

critical thinking The process of assess­ing claims and making judgments on the basis of well-supported evidence-

culture The accumulation of values- rules of behavior- forms of expression- religious beliefs- and occupational choices for a group of people who share a common language and environment-

cyclothymic disorder A mood disorder characterized by an alternating pattern of mood swings that are less extreme than those seen in bipolar disorder-






dark adaptation The increasing ability to see in the dark as time passes-

data Numbers that represent research findings and provide the basis for conclusions-

decay The gradual disappearance of information from memory-

defense mechanisms Unconscious tactics that either prevent threatening material from surfacing or disguise it when it does-

deindividuation A psychological state occurring in group members that results in loss of individuality and a tendency to do things not normally done when alone-

delusions False beliefs- such as those experienced by people suffering from schizophrenia or severe depression-

dendrites Fibers that receive signals from the axons of other neurons-

deoxyribonucleic acid (DNA) The molecular structure of a gene that provides the genetic code-

dependent variable In an experiment- the factor affected by the independent variable-

depressants Psychoactive drugs that inhibit the functioning of the central nervous system-

depth perception Perception of distance- allowing us to experience the world in three dimensions-

developmental psychologists Psychologists who seek to understand- describe- and explore how behavior and mental processes change over the course of a lifetime-

developmental psychology The psychological specialty that documents the course of people’s social- emotional- moral- and intellectual development over the life span-

diathesis-stress An approach that recognizes the roles of both predispositions and situational factors in the appearance of psychological disorders-

discrimination Differential treatment of people in certain groups; the behavioral component of prejudice-

discriminative stimuli Stimuli that signal whether reinforcement is available if a certain response is made-

diseases of adaptation Illnesses caused or worsened by stressors-

dissociation theory A theory proposing that hypnosis is a socially agreed-upon opportunity to display one’s ability to let mental functions become dissociated-

dissociative amnesia A psychological disorder marked by a sudden loss of memory for one’s own name- occupation- or other identifying information-

dissociative disorders Conditions involving sudden and usually temporary disruptions in a person’s memory- consciousness- or identity-

dissociative fugue A psychological disorder involving sudden loss of memory and the assumption of a new identity in a new locale-

dissociative identity disorder (DID) A dissociative disorder in which a person appears to have more than one identity- each of which speaks and acts in a different way-

divergent thinking The ability to generate many different solutions to a problem-

double-blind design A research design in which neither the experimenter nor the participants know who is in the experimental group and who is in the control group-

dreams Story-like sequences of images- sensations- and perceptions that last from several seconds to many minutes and occur mainly during REM sleep-

drive A physiological state that arises from an imbalance in homeostasis and prompts action to fulfill a need-

drive reduction theory A theory stating that motivation arises from imbalances in homeostasis-

dysthymic disorder A pattern of depression in which the person shows the sad mood- lack of interest- and loss of pleasure associated with major depressive disorder- but to a lesser degree and for a longer period-






eardrum A tightly stretched membrane in the middle ear that generates vibrations that match the sound waves striking it- Also known as the tympanic membrane-

educational psychologists Psychologists who study methods by which instructors teach and students learn- and who apply their results to improving such methods-

ego According to Freud- the part of the personality that makes compromises and mediates conflicts between and among the demands of the id- the superego- and the real world-

elaboration likelihood model A model of attitude change suggesting that people can change their attitudes through a central route (by considering an argument’s content) or through a peripheral route (in which they rely on irrelevant persuasion cues)-

elaborative rehearsal A memorization method that relates new information to information already stored in memory-

Electra complex The notion that young girls develop an attachment to the father and compete with the mother for the father’s attention-

electroconvulsive therapy (ECT) A brief electric shock administered to the brain- usually to reduce severe depression that does not respond to drug treatments-

embryo The developing individual from two weeks to two months after fertilization-

emotion A temporary positive or negative experience that is felt as happening to the self- that is generated partly by mental assessment of situations- and accompanied by learned and innate physical responses-

empathy In client-centered therapy- the therapist’s attempt to appreciate how the world looks from the client’s point of view-

empathy-altruism theory A theory suggesting that people help others because they feel empathy toward them-

empirically supported therapies (ESTs) Treatments for psychological disorders whose effectiveness has been validated by controlled experimental research-

empiricism The view that knowledge comes from experience and observation-

encoding specificity principle A principle stating that the ability of a cue to aid retrieval depends on whether it taps into information that was originally encoded-

encoding The process of putting information into a form that the memory system can accept and use-

endocrine system Cells that form organs called glands and that communicate with one another by secreting hormones-

engineering psychologists Psychologists who study- and try to improve- the relationships between human beings and the computers and other machines they use-

environmental psychologists Psychologists who study the relationship between people’s physical environment and their behavior-

environmental psychology The study of the effects of the physical environment on people’s behavior and mental processes-

episodic memory A person’s recall of a specific event that happened while the person was present-

escape conditioning The process of learning responses that terminate an aversive stimulus-

estrogens Feminine hormones that circulate in the bloodstream-

ethnic identity The part of a person’s identity that reflects the racial- religious- or cultural group to which he or she belongs-

evolutionary approach A view that emphasizes the inherited- adaptive aspects of behavior and mental processes-

excitation transfer The process by which arousal is carried over from one experience to an independent situation-

existence- relatedness- growth (ERG) theory A theory of motivation that focuses on employees’ needs at the level of existence- relatedness- and growth-

expectancy theory A theory of workplace motivation in which employees act in accordance with expected results and how much they value those results-

expected value The total benefit to be expected of a decision if it were repeated on several occasions-

experiment A situation in which the researcher manipulates one variable and observes the effect of that manipulation on another variable- while holding all other variables constant-

experimental group The group that receives the experimental treatment-

experimenter bias A confounding variable that occurs when an experimenter unintentionally encourages participants to respond in a way that supports the hypothesis-

explicit memory The process through which people deliberately try to remember something-

extinction The gradual disappearance of a conditioned response-






familial retardation Cases of mild retardation for which no environmental or genetic cause can be found-

family therapy A type of treatment involving two or more clients from the same family-

feature detectors Cells in the cortex that respond to a specific feature of an object-

fetal alcohol syndrome A pattern of defects found in babies born to women who drink heavily during pregnancy-

fetus The developing individual from the third month after conception until birth-

fiber tracts Bundles of axons that travel together-

fight-or-flight syndrome Physical reactions initiated by the sympathetic nervous system that prepare the body to fight or to run from a threatening situation-

figure The part of the visual field that has meaning-

five-factor model A view based on factor-analytic studies suggesting the existence of five basic components of human personality: neuroticism- extraversion- openness- agreeableness- and conscientiousness- Also called the big-five factor model-

flooding A procedure for reducing anxiety that involves keeping a person in a feared- but harmless- situation-

forebrain The part of the brain responsible for the most complex aspects of behavior and mental life-

forensic psychologists Psychologists who are involved in many aspects of psychology and law-

formal concept A concept that can be clearly defined by a set of rules or properties-

formal operational period According to Piaget- the fourth stage of cognitive development- characterized by the ability to engage in hypothetical thinking-

formal reasoning A set of rigorous procedures for reaching valid conclusions-

fovea A region in the center of the retina-

frequency The number of complete waves- or cycles- that pass a given point per unit of time-

frustration-aggression hypothesis A proposition stating that the existence of frustration always leads to some form of aggressive behavior-

functional fixedness The tendency to think about familiar objects in familiar ways-

fundamental attribution error A bias toward overattributing the behavior of others to internal factors-






gate control theory A theory suggesting the presence of a “gate” in the spinal cord that either permits or blocks the passage of pain impulses to the brain-

gender roles Patterns of work- appearance- and behavior that society associates with being male or female-

general adaptation syndrome (GAS) A three-stage pattern of responses triggered by the effort to adapt to stressors-

generalized anxiety disorder A condition that involves long-lasting anxiety that is not focused on any particular object or situation-

generativity The concern of adults in their forties with generating something enduring-

genes Hereditary units- located on chromosomes- that contain biological instructions inherited from both parents- providing the blueprint for physical development-

genital stage The fifth and last of Freud’s psychosexual stages- which begins during adolescence- when sexual impulses begin to appear at the conscious level-

Gestalt therapy A form of treatment that seeks to create conditions in which clients can become more unified- more self-aware- and more self-accepting-

glands Organs that secrete hormones into the bloodstream-

glial cells Cells that hold neurons together- direct growth- and help restore damaged neurons-

goal-setting theory A theory of workplace motivation focused on the idea that employees’ behavior is shaped by their intention to achieve specific goals-

grammar A set of rules for combining the symbols- such as words- used in a given language-

ground The contourless part of the visual field; the background-

group therapy Psychotherapy involving six to twelve unrelated individuals-

groupthink A pattern of thinking that renders group members unable to evaluate realistically the wisdom of various options and decisions-






habituation Reduced responsiveness to a repeated stimulus-

hallucinations False or distorted perceptions of objects or events-

hallucinogens Psychoactive drugs that alter consciousness by producing a temporary loss of contact with reality and changes in emotion- perception- and thought-

health promotion The process of altering or eliminating behaviors that pose risks to health and- at the same time- fostering healthier behavior patterns-

health psychologists Psychologists who study the effects of behavior on health and the impact of illness on behavior and emotion-

health psychology A field in which psychologists conduct and apply psychological research to promote human health and prevent illness-

helping behavior Any act that is intended to benefit another person-

heterosexual Referring to sexual desire or behavior that is focused on members of the opposite sex-

heuristics Mental shortcuts or rules of thumb-

hindbrain The portion of the brain that lies just inside the skull and is a continuation of the spinal cord-

hippocampus A forebrain structure associated with the formation of new memories-

homeostasis The tendency for physiological systems to remain at a stable- steady level by constantly adjusting themselves in response to change-

homosexual Referring to sexual desire or behavior that is focused on members of a person’s own sex-

hormones Chemicals secreted by glands into the bloodstream- allowing stimulation of cells that are not directly connected-

hue The essential color determined by the dominant wavelength of a light-

humanistic approach A view of behavior as controlled by the decisions that people make about their lives based on their perceptions of the world-

hunger The general state of wanting to eat-

hypnosis An altered state of consciousness brought on by special techniques- characterized by varying degrees of responsiveness to suggestions for changes in experience and behavior-

hypnotic susceptibility The degree to which a person responds to hypnotic suggestion-

hypochondriasis A strong- unjustified fear of physical illness-

hypothalamus A forebrain structure that regulates hunger- thirst- and sex drives- with many connections to and from the autonomic nervous system and other parts of the brain-

hypothesis In scientific research- a specific- testable proposition about a phenomenon-






id According to Freud- a personality component containing basic instincts- desires- and impulses with which all people are born-

identity crisis The phase during which an adolescent attempts to develop an integrated self-image as a unique person by pulling together self-knowledge acquired during childhood-

images Mental representations of visual information-

immediate memory span The maximum number of items a person can recall perfectly after one presentation of the items-

immune system The body’s first line of defense against invading substances and microorganisms-

impaired functioning Difficulty in fulfilling appropriate and expected social roles-

implicit memory The unintentional recollection and influence of prior experiences-

incentive theory A theory stating that people are pulled toward behaviors offering positive incentives and pushed away from behaviors associated with negative incentives-

independent variable In an experiment- the variable manipulated by the researcher-

industrial/organizational (I/O) psychology The science of behavior and mental processes in the workplace-

industrial/organizational psychologists Psychologists who examine factors that influence people’s performance in the workplace-

informal reasoning Assessment of a conclusion’s validity based on the evidence available to support it-

information processing The process of taking in- remembering or forgetting- and using information-

information-processing model A model suggesting that information must pass through sensory memory- short-term memory- and long-term memory in order to become firmly embedded in memory-

information-processing system Mechanisms for receiving information- representing it with symbols- and manipulating it-

insight An understanding about what is required to produce a desired effect-

insomnia A sleep disorder in which a person feels tired during the day because of trouble falling asleep or staying asleep at night-

instinct theory A view that explains human behavior as motivated by automatic- involuntary- and unlearned responses-

instincts Innate- automatic dispositions to respond in particular ways to specific stimuli-

intelligence quotient (IQ score) A number that reflects the degree to which a person’s score on an intelligence test differs from the average score of others in his or her age group-

intelligence The possession of knowledge- the ability to efficiently use that knowledge to reason about the world- and the ability to use that reasoning adaptively in different environments-

interference The process through which storage or retrieval of information is impaired by the presence of other information-

internal noise The spontaneous- random firing of nerve cells that occurs because the nervous system is always active-

IQ test A test designed to measure intelligence on an objective- standardized scale-

iris The part of the eye that gives it its color and adjusts the amount of light entering it-






jet lag Fatigue- irritability- inattention- and sleeping problems caused by air travel across several time zones-

job analysis The process of collecting information about jobs and job requirements that is used to guide hiring and training decisions-

job performance appraisal The process of evaluating how well employees are doing in various aspects of their work-

job satisfaction The degree to which people like or dislike their jobs-

just-noticeable difference (JND) The smallest detectable difference in stimulus energy- Also called difference threshold-






kinesthesia The proprioceptive sense that tells us where the parts of the body are with respect to one another-






language Symbols- and a set of rules for combining them- used as a means of communicating-

latency period The fourth of Freud’s psychosexual stages- usually beginning during the fifth year of life- in which sexual impulses become dormant and the child focuses on education and other matters-

latent learning Learning that is not demonstrated at the time it occurs-

law of effect A law stating that if a response made in the presence of a particular stimulus is rewarded- the same response is more likely to occur when that stimulus is encountered again-

leader-member exchange (LMX) theory A theory suggesting that leaders tend to supervise in-group and out-group employees in different ways-

learned helplessness A process in which a person or animal stops trying to exert control after experience suggests that no control is possible-

learning The modification of pre-existing behavior and understanding-

lens The part of the eye directly behind the pupil-

levels-of-processing model A model of memory suggesting that differences in how well something is remembered reflect the degree or depth of mental processing-

light intensity A physical dimension of light waves that refers to how much energy the light contains and that determines its brightness-

light wavelength A physical dimension of light waves that refers to their length and that produces sensations of different colors-

long-term memory (LTM) The stage of memory for which the capacity to store new information is believed to be unlimited-

looming A motion cue whereby rapid expansion in the size of an image fills the available space on the retina-

loudness A psychological dimension of sound determined by the amplitude of a sound wave-

lucid dreaming Being aware that a dream is a dream while it is occurring-






maintenance rehearsal A memorization method that involves repeating information over and over to keep it in memory-

major depressive disorder A condition in which a person feels sad and hopeless for weeks or months- often losing interest in all activities and taking pleasure in nothing-

mania An elated- active emotional state-

matching hypothesis A proposition stating that people are most likely to date- marry- or form committed relationships with others who are similar to themselves in physical attractiveness-

maturation Natural growth or change triggered by biological factors independent of the environment-

medulla The area of the hindbrain that controls vital autonomic functions such as heart rate- blood pressure- and breathing-

mental models Sets of propositions that represent people’s understanding of how things look and work-

mental set The tendency for old patterns of problem solving to persist-

method of savings A method for measuring forgetting-

midbrain A small structure between the hindbrain and the forebrain that helps produce smooth movements-

midlife transition A point at around age forty when adults take stock of their lives-

mnemonics Strategies for organizing information in order to remember it-

modeling A method of therapy in which desirable behaviors are demonstrated as a way of teaching them to clients-

mood disorder A condition in which a person experiences extremes of mood for long periods- shifts from one extreme mood to another- and experiences moods that are inconsistent with events-

motivation The influences that account for the initiation- direction- intensity- and persistence of behavior-

motive A reason or purpose for behavior-

motor cortex The part of the cerebral cortex that controls voluntary movement-






narcolepsy A daytime sleep disorder in which a person suddenly switches from an active waking state into REM sleep-

natural concepts Concepts that have no fixed set of defining features but instead share a set of characteristic features-

naturalistic observation The process of watching without interfering as a phenomenon occurs in the natural environment-

need A biological requirement for well-being-

need achievement A motive reflected in the degree to which a person establishes specific goals- cares about meeting those goals- and experiences feelings of satisfaction by doing so-

negative reinforcers The removal of unpleasant stimuli- such as pain- that strengthens responses that precede the removal-

nervous system A network of billions of cells that detects what is going on inside and outside the body and guides appropriate responses-

neurobiological model A view of mental disorder as caused by physical illness or an imbalance in bodily processes- including disturbances in the anatomy and chemistry of the brain-

neuroleptics Drugs that relieve the symptoms of schizophrenia or other severe forms of psychological disorder- Also called antipsychotics-

neurons Specialized cells of the nervous system that send and receive messages-

neurotransmitter A chemical that transfers messages across synapses-

night terrors Horrific dream images during stage 4 sleep- followed by a rapid awakening and a state of intense fear-

nightmares Frightening dreams that take place during REM sleep-

nonconscious level The level of consciousness at which reside processes that are totally inaccessible to conscious awareness-

norms (social) Learned- socially based rules that prescribe what people should or should not do in various situations-

norms (test-related) Descriptions of the frequency of particular scores on a test-

nuclei Clusters of nerve cell bodies in the central nervous system-






obedience A form of compliance in which people comply with a demand from an authority figure-

obesity A condition in which a person is severely overweight-

object permanence The knowledge that an object exists even when it is not in view-

objective personality test A form listing clear- specific questions- statements- or concepts to which people are asked to respond-

observational learning Learning by watching the behavior of others-

obsessive-compulsive disorder (OCD) An anxiety disorder in which a person becomes obsessed with certain thoughts or feels a compulsion to do certain things-

occupational health psychology A field concerned with psychological factors that affect the health- safety- and well-being of employees-

Oedipus complex The notion that young boys’ impulses involve sexual feelings for the mother and the desire to eliminate the father-

olfactory bulb A brain structure that receives messages regarding smell-

operant A response that has some effect on the world-

operant conditioning A process in which responses are learned on the basis of their rewarding or punishing consequences-

operational definitions Statements that define phenomena or variables by describing the exact research operations or methods used in measuring or manipulating them-

opiates Psychoactive drugs that have the ability to produce both sleep-inducing and pain-relieving effects-

opponent-process theory A theory of color vision stating that the visual elements sensitive to color are grouped into red-green- blue-yellow- and black-white elements-

optic nerve A bundle of fibers that carries visual information to the brain-

oral stage The first of Freud’s psychosexual stages- occurring during the first year of life- in which the mouth is the center of pleasure-

organizational citizenship behavior (OCB) A willingness to go beyond formal job requirements in order to help co-workers and/or the organization-






pain disorder A somatoform disorder marked by complaints of severe- often constant pain with no physical cause-

panic disorder Anxiety in the form of severe panic attacks that come without warning or obvious cause-

papillae Structures in the mouth- on which taste buds are grouped-

parallel distributed processing (PDP) models Models of memory suggesting that new experiences provide specific information- but also become part of- and alter- a whole network of associations in a person’s knowledge base-

parasympathetic nervous system The subsystem of the autonomic nervous system that typically influences activity related to the protection- nourishment- and growth of the body-

partial reinforcement extinction effect A phenomenon in which behaviors learned under a partial reinforcement schedule are more difficult to extinguish than those learned on a continuous reinforcement schedule-

perception The process through which people take raw sensations from the environment and give them meaning- using knowledge- experience- and understanding of the world-

perceptual constancy The perception of objects as retaining the same size- shape- color- and other properties despite changes in their retinal image-

performance scale Subtests in Wechsler tests that measure spatial ability and the ability to manipulate materials as part of a measure of overall intelligence-

peripheral nervous system The part of the nervous system that sends messages to and from the central nervous system-

permissive parents Parents who give their children complete freedom and lax discipline-

personality disorders Long-standing- inflexible ways of behaving that become styles of life that create problems- usually for others-

personality psychologists Psychologists who focus on people’s unique characteristics-

personality The pattern of psychological and behavioral characteristics by which each person can be compared and contrasted with other people-

person-centered therapy A type of therapy in which the client decides what to talk about and when- without direction- judgment- or interpretation from the therapist- Also called client-centered therapy-

person-oriented leaders Leaders who provide loose supervision- ask for group members’ ideas- and are generally concerned with subordinates’ feelings-

phallic stage The third of Freud’s psychosexual stages- lasting from approximately ages three to five- in which the focus of pleasure shifts to the genital area-

pheromones Chemicals that are released by one animal and detected by another- shaping the second animal’s behavior or physiology-

phobia An anxiety disorder that involves strong- irrational fear of an object or situation that does not objectively justify such a reaction-

photoreceptors Specialized cells in the retina that convert light energy into neural activity-

pinna The crumpled part of the outer ear that collects sound waves-

pitch How high or low a tone sounds; pitch depends on the frequency of a sound wave-

place theory A theory of hearing stating that hair cells at a particular place on the basilar membrane respond most to a particular frequency of sound-

placebo A treatment that contains no active ingred­ient but produces an effect because the person receiving it believes it will-

plasticity A property of the central nervous system that has the ability to strengthen neural connections at synapses- as well as to establish new connections-

pleasure principle The operating principle of the id- which guides people toward whatever feels good-

positive reinforcement Presenting a positive reinforcer (reward) after a desired response-

positive reinforcers Stimuli that strengthen a response if they follow that response-

postconventional Referring to moral reasoning that reflects moral judgments based on personal standards or universal principles of justice- equality- and respect for human life-

posttraumatic stress disorder (PTSD) A pattern of adverse reactions following a traumatic event- commonly involving re-experiencing the event through nightmares or vivid memories-

preconscious level The level at which reside mental events that are not currently conscious but can become conscious at will-

preconventional Referring to moral reasoning that is not based on the conventions or rules that guide social interactions in a society-

prejudice A positive or negative attitude toward people in certain groups-

preoperational period According to Piaget- the second stage of cognitive development- during which children begin to understand- create- and use symbols that represent things that are not present-

primacy effect A phenomenon whereby recall for the first two or three items in a list is particularly good-

primary drives Drives that arise from basic biological needs-

primary reinforcers Events or stimuli that satisfy physiological needs basic to survival-

proactive interference A cause of forgetting whereby previously learned information interferes with the ability to remember new information-

procedural memory A type of memory containing information about how to do things-

progestins Feminine hormones that circulate in the bloodstream-

projective personality tests Personality tests made up of relatively unstructured stimuli in which responses are seen as reflecting the individuals’ unconscious needs- fantasies- conflicts- thought patterns- and other aspects of personality-

propositions Mental representations that express a relationship between concepts-

proprioceptive Referring to sensory systems that tell us about the location of our body parts and what each is doing-

prototype A member of a natural concept that possesses all or most of its characteristic features-

psychiatrists Medical doctors who have completed special training in the treatment of mental disorders-

psychoactive drugs Chemical substances that act on the brain to create psychological effects-

psychoanalysis A method of psychotherapy that seeks to help clients gain insight into- and work through- unconscious thoughts and emotions presumed to cause psychological problems-

psychodynamic approach A view developed by Freud emphasizing uncon­scious mental processes in explaining human thought- feelings- and behavior-

psychological dependence A condition in which a person continues drug use despite adverse effects- needs the drug for a sense of well-being- and becomes preoccupied with obtaining the drug if it is unavailable-

psychological model An approach that views mental disorder as arising from inner turmoil or other psychological processes-

psychologists In the area of treatment- therapists with advanced training in clinical or counseling psychology-

psychology The science that seeks to understand behavior and mental processes and to apply that understanding in the service of human welfare-

psychoneuroimmunology The field that examines the interaction of psychological and physiological processes affecting the body’s ability to defend itself against disease-

psychopathology Patterns of thinking and behaving that are maladaptive- disruptive- or uncomfortable for the affected person or for others-

psychopharmacology The study of psychoactive drugs and their effects-

psychosexual stages In Freud’s psychodynamic theory- periods of personality development in which internal and external conflicts focus on particular issues-

psychotherapy The treatment of psychological disorders through psychological methods- such as analyzing problems- talking about possible solutions- and encouraging more adaptive ways of thinking and acting-

puberty The condition of being able- for the first time- to reproduce-

punishment The presentation of an aversive stimulus or the removal of a pleasant one following some behavior-

pupil An opening in the eye- just behind the cornea- through which light passes-






quantitative psychologists Psychologists who develop statistical methods for evaluating and analyzing data from psychological research-






random assignment A procedure through which random variables are evenly distributed in an experiment by placing participants in experimental and control 1groups on the basis of a coin flip or some other random process-

random sample A group of research participants selected from a population each of whose members had an equal chance of being chosen

random variables Uncontrolled or uncontrollable factors that affect the dependent variable along with- or instead of- the independent variable-

rapid eye movement (REM) sleep The stage of sleep during which the EEG resembles that of someone who is awake- but muscle tone decreases dramatically-

rational-emotive behavior therapy (REBT) A treatment that involves identifying illogical- self-defeating thoughts that clients have learned- then helping clients replace these maladaptive thought with more realistic and beneficial ones-

reality principle The operating principle of the ego- which takes into account the constraints of the social world-

recency effect A phenomenon whereby recall for the last few items in a list is particularly good-

receptors Cells specialized to detect certain types of energy and convert it into neural activity-

reconditioning The relearning of a conditioned response following extinction-

reference groups Categories of people with whom individuals compare themselves-

reflection Restating or paraphrasing what the client has said-

reflexes Simple- involuntary- unlearned behaviors directed by the spinal cord without instructions from the brain-

refractory period A short recovery time after cell firing- during which the cell cannot fire again-

reinforcer A stimulus event that increases the probability that the response immediately preceding it will occur again-

relative deprivation The sense that one is not getting all that one deserves-

reliability The degree to which test results or other research evidence occurs repeatedly-

REM behavior disorder A sleep disorder in which a person fails to show the decreased muscle tone normally seen in REM sleep- thus allowing the person to act out dreams-

representativeness heuristic A mental shortcut that involves judging whether something belongs in a given class on the basis of its similarity to other members of that class-

response criterion The internal rule a person uses to decide whether or not to report a stimulus-

reticular formation A collection of cells and fibers in the hindbrain and midbrain that are involved in arousal and attention-

retina The surface at the back of the eye onto which the lens focuses light rays-

retrieval cues Stimuli that allow or help people to recall information-

retrieval The process of recalling information stored in memory-

retroactive interference A cause of forgetting whereby new information placed in memory interferes with the ability to recall information already in memory-

retrograde amnesia A loss of memory for events that occurred prior to a brain injury-

rods Photoreceptors in the retina that allow sight even in dim light- but that cannot discriminate colors-

role theory A theory proposing that hypnotized people act in accordance with a social role that demands compliance-

rules of logic A set of statements that provide a formula for drawing valid conclusions-






sampling The process of selecting participants who are members of the population that the researcher wishes to study-

satiety The condition of no longer wanting to eat-

saturation The purity of a color-

schemas Generalized mental representations of objects- places- events- people- and social situations-

schizophrenia A pattern of severely disturbed thinking- emotion- perception- and behavior that constitutes one of the most serious and disabling of all mental disorders-

school psychologists Psychologists who test IQ- diagnose students’ academic problems- and set up programs to improve students’ achievement-

scripts Mental representations of familiar sequences of activity-

secondary drives Stimuli that take on the motivational properties of primary drives through learning-

secondary reinforcers Rewards that people or animals learn to like-

second-order conditioning A process in which a conditioned stimulus acts like an unconditioned stimulus- creating conditioned stimuli out of events associated with it-

selective attention The process of focusing mental resources on only part of the stimulus field-

self-concept The way one thinks of oneself-

self-efficacy According to Bandura- the learned expectation of success in given situations-

self-esteem The evaluations people make about their worth as human beings

self-fulfilling prophecy A process in which an initial impression causes us to bring out behavior in another that confirms the impression-

self-serving bias The cognitive tendency to attribute one’s successes to internal characteristics while blaming one’s failures on external causes-

semantic codes Mental representations of experiences by their general meaning-

semantic memory A type of memory containing generalized knowledge of the world-

sensations Raw information from the senses-

sense A system that translates data from outside the nervous system into neural activity-

sense of smell The sense that detects chemicals that are airborne- Also called olfaction-

sense of taste The sense that detects chemicals in solution that come into contact with receptors inside the mouth- Also called gustation-

sensitivity The ability to detect a stimulus-

sensorimotor period According to Piaget- the first stage of cognitive development- when the infant’s mental activity is confined to sensory perception and motor skills-

sensory cortex The part of the cerebral cortex located in the parietal- occipital- and temporal lobes that receives stimulus information from the skin- eyes- and ears- respectively-

sensory memory A type of memory that is very brief- but lasts long enough to connect one impression to the next-

sensory registers Memory systems that briefly hold incoming information-

sex hormones Chemicals in the blood that organize and motivate sexual behavior-

sexual dysfunctions Problems with sexual motivation- arousal- or orgasmic response-

sexual response cycle The pattern of arousal before- during- and after sexual activity-

shaping The reinforcement of responses that come successively closer to some desired response-

short-term memory (STM) A stage of memory in which information normally lasts less than twenty seconds; a component of working memory-

signal-detection theory A mathematical model of what determines a person’s report of a near-threshold stimulus-

sleep apnea A sleep disorder in which people briefly but repeatedly stop breathing during the night-

sleepwalking A phenomenon that starts primarily in non-REM sleep- especially in stage 4- and involves walking while asleep-

slow-wave sleep Sleep stages 3 and 4- which are accompanied by slow- deep breathing; a calm- regular heartbeat; and reduced blood pressure-

social cognition Mental processes associated with people’s perceptions of- and reactions to- other people-

social comparison Using other people as a basis of comparison for evaluating oneself-

social dilemmas Situations in which actions that produce rewards for one individual will produce negative consequences if they are adopted by everyone-

social facilitation A phenomenon in which the mere presence of other people improves a person’s performance on a given task-

social identity The beliefs we hold about the groups to which we belong-

social impairment A reduction in performance due to the presence of other people-

social loafing Exerting less effort when performing a group task because one’s contribution cannot be identified-

social neuroscience A specialty that focuses on the influence of social processes on biological processes and on the influence of biological processes on social psychological phenomena-

social perception The processes through which people interpret information about others- draw inferences about them- and develop mental representations of them-

social phobias Strong- irrational fears relating to social situations-

social psychologists Psychologists who study how people influence one another’s behavior and attitudes- especially in groups-

social psychology The subfield of psychology that explores the effects of the social world on the behavior and mental processes of individuals and groups-

social referencing A phenomenon in which other people’s facial expressions- tone of voice- and bodily gestures serve as guidelines for how to behave in uncertain situations-

social support network The friends and social contacts on whom one can depend for help and support-

social-cognitive approach An approach to personality that views personality as a label summarizing the unique patterns of thinking and behavior that a person learns-

socialization The process by which parents- teachers- and others teach children the skills and social norms necessary to be well-functioning members of society-

sociocultural model An approach to explaining mental disorder that emphasizes the role of factors such as gender and age- physical situations- cultural values and expectations- and historical era-

sociocultural variables Social identity and other background factors- such as gender- ethnicity- social class- and culture-

somatic nervous system The subsystem of the peripheral nervous system that transmits information from the senses to the central nervous system and carries signals from the CNS to the muscles that move the skeleton-

somatic senses Senses including touch- temperature- pain- and kinesthesia that are spread throughout the body rather than located in a specific organ- Also called somatosensory systems

sound A repetitive fluctuation in the pressure of a medium such as air-

somatization disorder A psychological problem in which a person has numerous physical complaints without verifiable physical illness-

somatoform disorders Psychological problems in which a person shows the symptoms of some physical (somatic) disorder for which there is no physical cause-

specific phobias Phobias that involve fear and avoidance of heights- blood- animals- and other specific stimuli and situations-

spinal cord The part of the central nervous system that receives information from the senses- passes these signals to the brain- and sends messages from the brain to the body-

spontaneous recovery The reappearance of a conditioned response after extinction-

sport psychologists Psychologists whose research is aimed at maximizing athletic performance-

spreading activation In semantic network theories of memory- a principle that explains how information is retrieved-

Stanford-Binet A test for determining a person’s intelligence quotient- or IQ-

state of consciousness The characteristics of consciousness at any particular moment-

state theory A theory proposing that hypnosis creates an altered state of consciousness-

state-dependent memory Memory that is helped or hindered by similarities or differences in a person’s internal state during learning versus recall-

statistically significant Referring to a correlation- or a difference between two groups- that is larger than would be expected by chance-

stereotypes Impressions or schemas of an entire group of people that involve the false assumption that all members of the group share the same characteristics-

stimulants Psychoactive drugs that have the ability to increase behavioral and mental activity-

stimulus discrimination A process through which people learn to differentiate among similar stimuli and respond appropriately to each one-

stimulus generalization A process in which a conditioned response is elicited by stimuli similar to the original conditioned stimulus-

storage The process of maintaining information in the memory system over time-

stress reactions Physical and psychological responses to stressors-

stress The process of adjusting to circumstances that disrupt- or threaten to disrupt- a person’s daily functioning-

stressors Events or situations to which people must adjust-

stroboscopic motion An illusion in which lights or images flashed in rapid succession are perceived as moving-

subconscious Another term describing the mental level at which influential- but normally inaccessible- mental processes take place-

subjective well-being A combination of a cognitive judgment of satisfaction with life- the frequent experiencing of positive moods and emotions- and the relatively infrequent experiencing of unpleasant moods and emotions-

substance abuse The use of psychoactive drugs in ways that deviate from cultural norms-

substance-related disorders Problems involving the use of psychoactive drugs for months or years in ways that harm the user or others-4

sudden infant death syndrome (SIDS) A disorder in which a sleeping baby stops breathing but does not awaken and suffocates-

superego According to Freud- the component of personality that tells people what they should and should not do-

surveys Research that involves giving people questionnaires or inter­views designed to describe their attitudes- beliefs- opinions- and intentions-

sympathetic nervous system The subsystem of the autonomic nervous system that readies the body for vigorous activity-

synapse The tiny gap between the axon of one neuron and the dendrites of another-

systematic desensitization A behavioral method for treating anxiety in which clients visualize a graduated series of anxiety-provoking stimuli while maintaining a state of relaxation-






task-oriented leaders Leaders who provide close supervision- lead by giving directions- and generally discourage group discussion-

telegraphic A term referring to young children’s utterances that are brief and to the point and that leave out nonessential words-

temperament An individual’s basic- natural disposition- evident from infancy-

teratogens Harmful substances- such as alcohol and other drugs- that can cause birth defects-

terminal drop A sharp decline in mental functioning that tends to occur in late adulthood- a few months or years before death-

test A systematic observation of behavior in a standard situation- described by a numerical scale or category-

thalamus A forebrain structure that relays messages from most sense organs to higher brain areas-

theory An integrated set of proposi­tions used to explain certain phenomena- including behavior and mental processes-

thinking The manipulation of mental representations-

timbre The quality of a sound that identifies it-

token economy A system for improving the behavior of severely disturbed or mentally retarded clients in institutions by rewarding desirable behaviors with tokens that can be exchanged for various rewards-

tolerance A condition in which increasingly larger drug doses are needed to produce a given effect-

top-down processing Aspects of recognition guided by higher-level cognitive processes and psychological factors such as expectations-

trait approach A perspective on personality that views it as the combination of stable characteristics that people display over time and across situations-

transduction The process of converting incoming physical energy into neural activity-

transfer-appropriate processing model A model suggesting that memory depends on how the encoding process matches up with what is later retrieved-

trichromatic theory A theory of color vision stating that information from three types of visual elements combines to produce the sensation of color-






unconditional positive regard In client-centered therapy- the therapist’s attitude that expresses caring for- and acceptance of- the client as a valued person-

unconditioned response (UCR) The automatic- unlearned- reflexive reaction to a stimulus-

unconditioned stimulus (UCS) A stimulus that elicits a response without conditioning-

unconscious The term used to describe a level of mental activity said by Freud to contain unacceptable sexual- aggressive- and other impulses of which an individual is unaware-

utility In decision making- any subjective measure of value-






validation studies Research projects that determine how well a test- interview- or other assessment method predicts job performance-

validity The degree to which a test measures what it is supposed to measure and leads to correct inferences about people-

validity The degree to which evidence from a test or other research method measures what it is supposed to measure-

variables Specific factors or characteristics that can take on different numerical values in research-

verbal scale Subtests in Wechsler tests that measure verbal skills as part of a measure of overall intelligence-

vestibular sense The proprioceptive sense that provides information about the position of the head and its movements-

vicarious conditioning A kind of observational learning through which a person is influenced by watching or hearing about the consequences of others’ behavior-

visible light Electromagnetic radiation that has a wavelength of about 400 nanometers to about 750 nanometers-

visual codes Mental representations of stimuli as pictures-

volley theory A theory of hearing stating that the firing rate of an auditory nerve matches a sound wave’s frequency- Also called frequency-matching theory-






wavelength The distance between peaks in a wave of light or sound-

Weber’s law A law stating that the smallest detectable difference in stimulus energy (just-noticeable difference) is a constant fraction of the intensity of the stimulus-

withdrawal syndrome A set of symptoms associated with discontinuing the use of an addictive substance-

work group At least two people who interact with one another as they perform the same or different workplace tasks-

work team A work group in which the members’ specialized activities are coordinated and interdependent as they work toward a common goal-

working memory The part of the memory system that mentally works with- or manipulates- information being held in short-term memory-