K

kinesthetic: sense the sense that provides information about the position of the joints, the degree of tension in the muscles, and the movement of the arms and legs. (185)

L

language: a formal system of communication involving symbols, whether spoken, written, or gestured, and rules for combining them. (326)

latency stage: in Freud's theory, the stage, between age 5 and puberty, during which there is little psychosexual development. (446)

latent content: Sigmund Freud's term for the true, though disguised, meaning of a dream. (209)

latent learning: learning that occurs without the reinforcement of overt behavior. (261)

law of effect: Edward Thorndike's principle that a behavior followed by a satisfying state of affairs is strengthened and a behavior followed by an annoying state of affairs is weakened. (245)

lay psychology: psychological beliefs based on common sense or folk wisdom. (32)

learned helplessness: a feeling of futility caused by the belief that one has little or no control over events in one's life, which might make one stop trying and develop feelings of depression. (257, 571)

learning: a relatively permanent change in knowledge or behavior resulting from experience. (236)

leniency: the tendency to rate too positively. (662)

lens: the transparent structure behind the pupil that focuses light onto the retina. (157)

levels of processing theory: the theory that the depth at which we process information determines how well it is encoded, stored, and retrieved. (279)

libido: Freud's term for the sexual energy of the id. (446)

limbic system: a group of forebrain structures that promote the survival of the individual and, as a result, the continuation of the species by their influence on emotion, motivation, and memory. (83)

line graph: a graph used to plot data showing the relationship between independent an dependent variables in an experiment. (645)

linguistic relativity hypothesis: Whorf's hypothesis that one's perception of the world is molded by one's language. (334)

link method: a mnemonic device that involves connecting, in sequence, images of items to be memorized, to make them easier to recall. (295)

logical concept: a concept formed by identifying the specific features possessed by all things that the concept applies to. (311)

logotherapy: a form of existential therapy, developed by Victor Frankl, that helps the client find meaning in life. (534)

longitudinal research: a research design in which the same group of subjects is tested or observed repeatedly over a period of time. (111)

long-term memory: the stage of memory that can store a virtually unlimited amount of information relatively permanently. (273)

loudness perception: the subjective experience of the intensity of a sound, which corresponds most closely to the amplitude of the sound waves composing it. (177)

LSD: a hallucinogen derived from a fungus that grows on rye grain. (223) lucid dreaming: the ability to be aware that one is dreaming and to direct one's dreams. (209)

M

magnetic resonance imaging (MRI): a brain-scanning technique that relies on strong magnetic fields to construct computer-generated images of the brain or body. (87)

maintenance rehearsal: repeating information to oneself to keep it in short-term memory. (277)

major depression: a mood disorder marked by depression so intense and prolonged that the person may be unable to function in everyday life. (494)

mania: a mood disorder marked by euphoria, hyperactivity, grandiose ideas, annoying talkativeness, unrealistic optimism, and inflated self-esteem. (497)

manifest content: Sigmund Freud's term for the verbally reported dream. (209)

massed practice cramming: the memorization of information or the learning of a motor skill into one session. (293)

maturation: the sequential unfolding of inherited predispositions in physical and motor development. (106)

mean: the arithmetic average of a set of scores. (53, 646)

mean length of utterance (MLU): the average length of spoken statements, used as a measure of language development in children. (331)

measurement: the use of numbers to represent events or characteristics. (38)

measure of central tendency: a statistic that represents the typical score in a set of scores. (53)

measure of variability: a statistic describing the degree of dispersion in a set of scores. (54)

median: the middle score in a set of scores that have been ordered from lowest to highest. (53, 646)

meditation: a procedure that uses mental exercises to achieve a highly focused state of consciousness. (217)

medulla oblongata (medulla): a hindbrain structure that regulates breathing, heart rate, blood pressure, and other life functions. (80)

memory: the process by which information is acquired, stored in the brain, later retrieved, and eventually possibly forgotten. (272)

menarche: the beginning of menstruation, usually occurring between the ages of 11 and 13. (131)

mental giftedness: intellectual superiority marked by an IQ above 130 and exceptionally high scores on achievement tests in specific subjects, such as mathematics. (356)

mental retardation: intellectual deficiency marked by an IQ below 70 and difficulties performing in everyday life. (353)

mental set: a tendency to use a particular problem-solving strategy that has succeeded in the past but that may interfere with solving a problem requiring a new strategy. (317)

mental telepathy: the alleged ability to perceive the thoughts of others without any sensory contact with them. (187)

meta-analysis: a technique that combines the results of many similar studies to determine the size and consistency of the effect of a particular kind of independent variable. (56)

method of loci: a mnemonic device in which items to be recalled are associated with landmarks in a familiar place and then recalled during a mental walk from one landmark to another. (294)

method of savings: the assessment of memory by comparing the time or number of trials needed to memorize a given amount of information and the time or number of trials needed to memorize it again at a later time. (284)

mnemonic devices: techniques for organizing information to be memorized to make it easier to remember. (294)

mode: the score that occurs most frequently in a set of scores. (53, 645)

monocular cues: depth perception cues that require input from only one eye. (168)

mood disorder: a psychological disorder marked by prolonged periods of extreme depression or elation, often unrelated to the person's current situation. (494)

moon illusion: the misperception that the moon is larger when it is at the horizon than when it is overhead. (171)

moral therapy: an approach to therapy, developed by Philippe Pinel, that provided mental patients with humane treatment. (519)

morpheme: the smallest meaningful unit of language. (328)

motivation: the psychological processes that arouse, direct, and maintain behavior toward a goal. (376)

motor cortex: the area of the frontal lobes that controls specific voluntary body movements. (84)

motor neuron: a neuron that sends messages from the central nervous system to smooth muscles, cardiac muscle, or skeletal muscles. (68)

myelin: a white fatty substance that forms sheaths around certain axons and increases the speed of neural impulses. (71)

myopia: visual nearsightedness, which is caused by an elongated eyeball. (157)

N

narcolepsy: a condition in which an awake person suffers from repeated, sudden, and irresistible REM sleep attacks. (206)

nativism: the philosophical position that heredity provides individuals with inborn knowledge and abilities. (5)

natural concept: a concept, typically formed through everyday experience, whose members possess some, but not all, of a common set of features. (312)

naturalistic observation: the recording of the behavior of subjects in their natural environments, with little or no intervention by the researcher. (40)

need: a motivated state caused by physiological deprivation, such as a lack of food or water. (377)

negative correlation: a correlation between two variables in which the variables tend to change in opposite directions. (46)

negative reinforcement: in operant conditioning, an increase in the probability of a behavior that is followed by the removal of an aversive stimulus. (251)

negative skew: a graph that has scores bunching up toward the positive end of the abscissa. (643)

negative state relief theory: the theory that we engage in prosocial behavior to relieve our own state of emotional distress at another's plight. (623)

neglect syndrome: a disorder, caused by damage to a parietal lobe, in which the individual acts as though the side of her or his world opposite to the damaged lobe does not exist. (66)

neodissociation theory: the theory that hypnosis induces a dissociated state of consciousness. (215)

nerve: a bundle of axons that conveys information to or from the central nervous system. (67)

nerve deafness: hearing loss caused by damage to the hair cells of the basilar membrane or the axons of the auditory nerve. (177)

nervous system: the chief means of communication in the body; the system of neurons, along which messages are transmitted. (67)

neural grafting: the transplantation of brain tissue or, in some cases, adrenal gland tissue into the brain or spinal cord to restore functions lost because of brain damage. (92)

neural plasticity: the ability of the brain to alter its neuronal pathways. (91)

neuron: a cell specialized for the transmission of information in the nervous system. (67)

neurosis: a general category, no longer widely used, that comprises psychological disorders associated with maladaptive attempts to deal with anxiety but with relatively good contact with reality. (482)

neurotransmitters: chemicals secreted by neurons that provide the means of synaptic transmission. (72)

nicotine: a stimulant used to regulate physical and mental arousal. (222)

nightmare: a frightening REM dream. (208)

night terror: a frightening NREM experience, common in childhood, in which the individual may suddenly sit up, let out a bloodcurdling scream, speak incoherently, and quickly fall back to sleep, yet usually fails to recall it on awakening. (208)

nominal scale: a scale of measurement that places objects, individuals, or characteristics into categories. (641)

norm: a score, based on the test performances of large numbers of subjects, that is used as a standard for assessing the performances of test takers. (44)

normal curve: a bell-shaped graph representing a hypothetical frequency distribution for a given characteristic. (648)

normative commitment: a felt obligation to stay with an organization. (667)

NREM sleep: the stages of sleep not associated with rapid eye movements and marked by relatively little dreaming. (201)

null hypothesis: the prediction that the independent variable will have no effect on the dependent variable in an experiment. (651)

O

obedience: following orders given by an authority. (619)

obesity: a body weight more than 20 percent above the norm for one's height and build. (381)

object permanence: the realization that objects exist even when they are no longer visible. (119)

observational learning: learning a behavior by observing the consequences that others receive for performing it. (261)

obsessive-compulsive disorder: an anxiety disorder in which the person has recurrent, intrusive thoughts (obsessions) and recurrent urges to perform ritualistic actions (compulsions). (490)

occipital lobe: a lobe of the cerebral cortex responsible for processing vision. (86)

Oedipus complex: in Freud's theory, a conflict, during the phallic stage, between the child's sexual desire for the parent of the opposite sex and fear of punishment from the same-sex parent. (446)

olfaction: the sense of smell, which detects molecules carried in the air. (179)

operant conditioning: B. F. Skinner's term for instrumental conditioning, a form of learning in which a behavior becomes more or less probable, depending on its consequences. (246)

operational definition: the definition of behaviors or qualities in terms of the procedures used to measure them. (38)

opiates: depressant drugs, derived from opium, used to relieve pain or to induce a euphoric state of consciousness. (221)

opponent-process theory of emotion: the theory that the brain counteracts a strong positive or negative emotion by evoking an opposite emotional response. (427)

opponent-process theory of vision: the theory that color vision depends on red- green, blue-yellow, and black-white opponent processes in the brain. (163)

optic chiasm: the point under the frontal lobes at which some axons from each of the optic nerves cross over to the opposite side of the brain. (159)

optic nerve: the nerve, formed from the axons of ganglion cells, that carries visual impulses from the retina to the brain. (157)

oral stage: in Freud's theory, the stage of personality development, between birth and age 1 year, during which the infant gains pleasure from oral activities and faces a conflict over weaning. (446)

ordinal scale: a scale of measurement that indicates the relative, but not exact, magnitude of scores. (641)

otolith organs: the vestibular organs that detect horizontal or vertical linear movement of the head. (186)

ovaries: the female gonads, which secrete hormones that regulate the development of the female reproductive system and secondary sex characteristics. (78)

overextension: the tendency to apply a word to more objects or actions than it actually represents. (330)

overjustification theory: the theory that an extrinsic reward will decrease intrinsic motivation when a person attributes her or his performance to that reward. (401)

overlearning: studying material beyond the point of initial mastery. (293)

overregularization: the application of a grammatical rule without making necessary exceptions to it. (331)

P

panic disorder: an anxiety disorder marked by sudden, unexpected attacks of overwhelming anxiety, often associated with the fear of dying or losing one's mind. (487)

parallel processing: the processing of different information simultaneously. (326)

paranoid schizophrenia: a type of schizophrenia marked by hallucinations, delusions, suspiciousness, and argumentativeness. (503)

paraphilia: a way of obtaining sexual gratification that violates legal or cultural norms concerning proper sex objects and sexual practices. (387)

parapsychology: the study of extrasensory perception, psychokinesis, and related phenomena. (187)

parasympathetic nervous system: the division of the autonomic nervous system that calms the body and serves maintenance functions. (67)

parietal lobe: a lobe of the cerebral cortex responsible for processing body sensations and perceiving spatial relations. (85)

Parkinson's disease: a degenerative disease of the dopamine pathway from the substantia nigra, which causes marked disturbances in motor behavior. (74)

partial schedule of reinforcement: a schedule of reinforcement that reinforces some, but not all, instances of a desired response. (249)

participant modeling: a form of social learning therapy in which the client learns to perform more-adaptive behaviors by first observing the therapist model the desired behaviors. (527)

passionate love: love characterized by intense emotional arousal and sexual feelings. (603)

Pearson's product-moment correlation: perhaps the most commonly used correlational statistic. (650)

pegword method: a mnemonic device that involves associating items to be recalled with objects that rhyme with the numbers 1, 2, 3, and so on, to make the items easier to recall. (295)

percentile: the score at or below which a particular percentage of scores fall. (649)

perception: the process that organizes sensations into meaningful patterns. (152)

perception without awareness: the unconscious perception of stimuli that normally exceed the absolute threshold but fall outside our focus of attention. (225)

performance appraisal: systematic review, evaluation, and feedback regarding an employee's job performance. (661)

peripheral nervous system: the division of the nervous system, composed of the nerves, that conveys sensory information to the central nervous system and motor commands from the central nervous system to the skeletal muscles and internal organs. (67)

personal construct: a hypothesis about social reality that is held by a person. (461)

personality: an individual's unique, relatively consistent pattern of thinking, feeling, and behaving. (442)

personality disorder: a psychological disorder characterized by enduring, inflexible, maladaptive patterns of behavior. (507)

personality psychology: the field that focuses on factors accounting for the differences in behavior and enduring personal characteristics among individuals. (21)

personal unconscious: in Jung's theory, the individual's own unconscious mind, which contains repressed memories. (448)

person-centered therapy: a type of humanistic therapy, developed by Carl Rogers, that helps clients find their own answers to their problems. (531)

person perception: the process of making judgments about the personal characteristics of others. (597)

persuasion: the attempt to influence the attitudes of other people. (606)

phallic stage: in Freud's theory, the stage of personality development, between ages 3 and 5, during which the child gains pleasure from the genitals and must resolve the Oedipus complex. (446)

phase advance: shortening the sleep-wake cycle, as occurs when traveling from west to east. (199)

phase delay: lengthening the sleep-wake cycle, as occurs when traveling from east to west. (200)

phenomenological psychology: a branch of humanistic psychology primarily concerned with the study of subjective mental experience. (17)

phenotype: the overt expression of an individual's genetic inheritance, which may also show the influence of the environment. (109)

phenylketonuria (PKU): a hereditary enzyme deficiency that, if left untreated in the infant, causes mental retardation. (355)

pheromones: odorous chemicals secreted by an animal that affect the behavior of other animals. (180)

phi phenomenon: apparent motion caused by the presentation of different visual stimuli in rapid succession. (12)

phobia: an anxiety disorder marked by excessive or inappropriate fear. (487)

phoneme: the smallest unit of sound in a language. (328)

phonology: the study of the sounds that compose languages. (328)

photopigments: chemicals, including rhodopsin and iodopsin, that enable the rods and cones to generate neural impulses. (160)

phrenology: a discredited technique for determining intellectual abilities and personality traits by examining the bumps and depressions of the skull. (89)

physiological reactivity: the extent to which a person displays increases in heart rate, blood pressure, stress hormone secretion, and other physiological activity in response to stressors. (570)

pie graph: a graph that represents data as percentages of a pie. (643)

pineal gland: an endocrine gland that secretes a hormone that has a general tranquilizing effect on the body and that helps regulate biological rhythms. (199)

pitch perception: the subjective experience of the highness or lowness of a sound, which corresponds most closely to the frequency of the sound waves that compose it. (176)

pituitary gland: an endocrine gland that regulates many of the other endocrine glands by secreting hormones that affect the secretion of their hormones. (76)

placebo: an inactive substance that may induce some of the effects of the drug for which it has been substituted. (51, 184)

place theory: the theory of pitch perception that assumes that hair cells at particular points on the basilar membrane are maximally responsive to sound waves of particular frequencies. (176)

pleasure principle: the process by which the id seeks immediate gratification of its impulses. (443)

polygraph test: the lie detector test, which assesses lying by measuring changing patterns of physiological arousal in response to particular questions. (434)

pons: a hindbrain structure that regulates the sleep-wake cycle. (81)

population: a group of individuals who share certain characteristics. (43)

pornography: sexually explicit material intended to incite sexual arousal. (630)

positive correlation: a correlation in which variables tend to change values in the same direction. (46)

positive reinforcement: in operant conditioning, an increase in the probability of a behavior that is followed by a desirable consequence. (246)

positive skew: a graph that has scores bunching up toward the negative end of the abscissa. (643)

positron-emission tomography (PET): a brain-scanning technique that produces color-coded pictures showing the relative activity of different brain areas. (87)

postconventional level: in Kohlberg's theory, the level of moral reasoning characterized by concern with obeying mutually agreed upon laws and by the need to uphold human dignity. (128)

posthypnotic suggestions: suggestions directing subjects to carry out particular behaviors or to have particular experiences after leaving hypnosis. (214)

posttraumatic stress disorder: a syndrome of physical and psychological symptoms that appears as a delayed response after exposure to an extremely emotionally distressing event. (562)

pragmatics: the relationship between language and its social context. (329)

precognition: the alleged ability to perceive events in the future. (188)

preconscious mind: the level of consciousness that contains feelings and memories that we are unaware of at the moment but can become aware of at will. (229)

preconventional level: in Kohlberg's theory, the level of moral reasoning characterized by concern with the consequences that behavior has for oneself. (128)

predictors: tests that measure the traits an employee needs in order to be successful at a job. (659)

prejudice: an attitude, usually negative, toward others, based on their membership in particular groups. (610)

Premack principle: the principle that a more probable behavior can be used as a reinforcer for a less probable one. (246)

preoperational stage: the Piagetian stage, extending from 2 to 7 years of age, during which the child's use of language becomes more sophisticated but the child has difficulty with the logical mental manipulation of information. (119)

presentism: an approach to history that studies the past in the context of current beliefs and knowledge. (4)

pressure: the emotional state induced when one is confronted by personal responsibilities that tax one's abilities. (559)

primary cortical areas: regions of the cerebral cortex that serve motor or sensory functions. (84)

primary reinforcer: in operant conditioning, an unlearned reinforcer, which satisfies a biological need such as air, food, or water. (246)

proactive interference: the process by which old memories interfere with the ability to remember new memories. (287)

problem solving: the thought process by which an individual overcomes obstacles to reach a goal. (313)

procedural memory: the long-term memory system that contains memories of how to perform particular actions or skills. (279)

programmed instruction: a step-by-step approach, based on operant conditioning, in which the learner proceeds at his or her own pace through more and more difficult material and receives immediate knowledge of the results of each response. (256)

progressive relaxation: a stress-reducing procedure that involves the successive tensing and relaxing of each of the major muscle groups of the body. (575)

projective test: a Freudian personality test based on the assumption that individuals project their unconscious feelings when responding to ambiguous stimuli. (450)

prosocial behavior: behavior that helps others in need. (622)

prosopagnosia: the inability to recognize faces, which is typically caused by damage to a region of the temporal and occipital lobes. (91)

prototype: the best representative of a concept. (312)

psychiatry: the field of medicine that diagnoses and treats psychological disorders by using medical or psychological forms of therapy. (22)

psychic determinism: the Freudian assumption that all human behavior is influenced by unconscious motives. (14)

psychoactive drugs: chemicals that induce changes in mood, thinking, perception, and behavior by affecting neuronal activity in the brain. 219

psychoanalysis: 1. the early school of psychology that emphasized the importance of unconscious causes of behavior. 2. a type of psychotherapy, developed by Sigmund Freud, aimed at uncovering the unconscious causes of psychological disorders. (13, 521)

psychoanalytic perspective: the psychological viewpoint that is descended from psychoanalysis, but which places less emphasis on biological motives and more emphasis on the importance of interpersonal relationships. (16)

psychodrama: a form of psychoanalytic group therapy, developed by Jacob Moreno, that aims at achieving insight and catharsis through acting out real-life situations. (535)

psychogenic amnesia: a dissociative disorder marked by the inability to recall personally significant memories. (492)

psychogenic fugue: a dissociative disorder marked by the memory loss characteristic of psychogenic amnesia, the loss of one's identity, and fleeing from one's home. (492)

psychokinesis (PK): the alleged ability to control objects with the mind alone. (188)

psychological hardiness: a personality characteristicÑmarked by feelings of commitment, challenge, and controlÑthat promotes resistance to stress. (572)

psychological test: a formal sample of a person's behavior, whether written or performed. (44)

psychology: the science of behavior and mental processes. (4)

psychoneuroimmunology: the interdisciplinary field that studies the relationship between psychological factors and physical illness. (566)

psychopathology: the study of psychological disorders. (478)

psychophysics: the study of the relationship between the physical characteristics of stimuli and the conscious psychological experiences they produce. (8, 152)

psychosis: a general category, no longer widely used, that comprises severe psychological disorders associated with thought disturbances, bizarre behavior, severe disruption of social relations, and relatively poor contact with reality. (482)

psychosurgery: the treatment of psychological disorders by destroying brain tissue. (539)

psychotherapy: the treatment of psychological disorders through psychological, as opposed to biomedical, means, generally involving verbal interaction with a professional therapist. (520)

puberty: the period of rapid physical change that occurs during adolescence, including the development of the ability to reproduce sexually. (130)

punishment: in operant conditioning, the process by which an aversive stimulus decreases the probability of a response that precedes it. (252)

pupil: the opening at the center of the iris that controls how much light enters the eye. (156)