Physiological dependence The process by which the body becomes adjusted to and dependent on a drug.
Pitch Sound quality of highness or lowness; primarily dependent on the frequency of the sound wave.
Pituitary gland Located in the brain, the gland that secretes growth hormone and influences the secretion of hormones by other endocrine glands.
Place theory The theory that different frequency tones produce maximum activation at different locations along the basilar membrane, with the result that pitch can be coded by the place at which activation occurs.
Placebo control An experimental condition in which treatment is not administered; it is used in cases where a placebo effect might occur.
Placebo effect A change in behavior in the absence of an experimental manipulation.
Placebo therapy A therapy independent of any specific clinical procedures that results in client improvement.
Pons The region of the brain stem that connects the spinal cord with the brain and links parts of the brain to one another.
Population The entire set of individuals to which generalizations will be made based on an experimental sample.
Positive punishment A behavior is followed by the presentation of an aversive stimulus, decreasing the probability of that behavior.
Positive reinforcement A behavior is followed by the presentation of an appetitive stimulus, increasing the probability of that behavior.
Possible selves The ideal selves that a person would like to become, the selves a person could become, and the selves a person is afraid of becoming; components of the cognitive sense of self.
Post Traumatic Stress Disorder (PTSD) An anxiety disorder characterized by the persistent reexperience of traumatic events through distressing recollections, dreams, hallucinations, or dissociative flashbacks; develops in response to rapes, life-threatening events, severe injuries, and natural disasters.
Preattentive processing Processing of sensory information that precedes attention to specific objects.
Preconscious memories Memories that are not currently conscious but that can easily be called into consciousness when necessary.
Predictive validity See criterion validity.
Prefrontal lobotomy An operation that severs the nerve fibers connecting the frontal lobes of the brain with the diencephalon, especially those fibers of the thalamic and hypothalamic areas; best-known form of psychosurgery.
Prejudice A learned attitude toward a target object, involving negative affect (dislike or fear), negative beliefs (stereotypes) that justify the attitude, and a behavioral intention to avoid, control, dominate, or eliminate the target object.
Primacy effect Improved memory for items at the start of a list.
Primary reinforcers Biologically determined reinforcers such as food and water.
Priming In the assessment of implicit memory, the advantage conferred by prior exposure to a word or situation.
Problem solving Thinking that is directed toward solving specific problems and that moves from an initial state to a goal state by means of a set of mental operations.
Problem space The elements that make up a problem: the initial state, the incomplete information or unsatisfactory conditions the person starts with; the goal state, the set of information or state the person wishes to achieve; and the set of operations, the steps the person takes to move from the initial state to the goal state.
Procedural memory Memory for how things get done; the way perceptual, cognitive, and motor skills are acquired, retained, and used.
Projective test A method of personality assessment in which an individual is presented with a standardized set of ambiguous, abstract stimuli and asked to interpret their meanings; the individual's responses are assumed to reveal inner feelings, motives, and conflicts.
Prosocial behaviors Behaviors that are carried out with the goal of helping other people.
Prototype The most representative example of a category.
Proximal stimulus The optical image on the retina; contrasted with the distal stimulus, the physical object in the world.
Psychiatrist An individual who has obtained an M.D. degree and also has completed postdoctoral specialty training in mental and emotional disorders; a psychiatrist may prescribe medications for the treatment of psychological disorders.
Psychic determinism The assumption that mental and behavioral reactions are determined by previous experiences.
Psychoactive drugs Chemicals that affect mental processes and behavior by temporarily changing conscious awareness of reality.
Psychoanalysis The form of psychodynamic therapy developed by Freud; an intensive and prolonged technique for exploring unconscious motivations and conflicts in neurotic, anxiety-ridden individuals.
Psychoanalyst An individual who has earned either a Ph.D. or an M.D. degree and has completed postgraduate training in the Freudian approach to understanding and treating mental disorders.
Psychobiography The use of psychological (especially personality) theory to describe and explain an individual's course through life.
Psychodynamic personality theories Theories of personality that share the assumption that personality is shaped by and behavior is motivated by powerful inner forces.
Psychodynamic perspective A psychological model in which behavior is explained in terms of past experiences and motivational forces; actions are viewed as stemming from inherited instincts, biological drives, and attempts to resolve conflicts between personal needs and social requirements.
Psychological assessment The use of specified procedures to evaluate the abilities, behaviors, and personal qualities of people.
Psychological dependence The psychological need or craving for a drug.
Psychological diagnosis The label given to psychological abnormality by classifying and categorizing the observed behavior pattern into an approved diagnostic system.
Psychologist An individual with a doctoral degree in psychology from an organized, sequential program in a regionally accredited university or professional school.
Psychology The scientific study of the behavior of individuals and their mental processes.
Psychometric function A graph that plots the percentage of detections of a stimulus (on the vertical axis) for each stimulus intensity (on the horizontal axis).
Psychometrics The field of psychology that specializes in mental testing.
Psychoneuroimmunology The research area that investigates interactions between psychological processes, such as responses to stress, and the functions of the immune system.
Psychopathological functioning Disruptions in emotional, behavioral, or thought processes that lead to personal distress or block one's ability to achieve important goals.
Psychopharmacology The branch of psychology that investigates the effects of drugs on behavior.
Psychophysics The study of the correspondence between physical stimulation and psychological experience.
Psychosocial stages Proposed by Erik Erikson, successive developmental stages that focus on an individual's orientation toward the self and others; these stages incorporate both the sexual and social aspects of a person's development and the social conflicts that arise from the interaction between the individual and the social environment.
Psychosomatic disorders Physical disorders aggravated by or primarily attributable to prolonged emotional stress or other psychological causes.
Psychosurgery A surgical procedure performed on brain tissue to alleviate a psychological disorder.
Psychotherapy Any of a group of therapies, used to treat psychological disorders, that focus on changing faulty behaviors, thoughts, perceptions, and emotions that may be associated with specific disorders.
Psychotic disorders Severe mental disorders in which a person experiences impairments in reality testing manifested through thought, emotional, or perceptual difficulties; no longer used as a diagnostic category after DSM-III.
Puberty The attainment of sexual maturity; indicated for girls by menarche and for boys by the production of live sperm and the ability to ejaculate.
Punisher Any stimulus that, when made contingent upon a response, decreases the probability of that response.