accommodation: According to Piaget, a mental process that involves altering old ways of thinking to incorporate new knowledge and information. 9
acetylcholine: A neurotransmitter found in various parts of the peripheral nervous system, in the spinal cord, and in specific regions of the brain. It plays an important role in learning and memory, and has been implicated in Alzheimer’s disease. 3
action potential: An abrupt change in a cell’s polarity that temporarily makes the cell’s interior positive and the cell’s exterior negative. This change travels the length of a neuronal axon. 3
activation-synthesis hypothesis: Proposed by J. A. Hobson, a theory of sleep and dreaming in which the often strange quality of dreams is thought to be caused by the brain trying to make sense of and impose order on random, meaningless neural activity. 5
actor-observer bias: The tendency to attribute one’s own behavior to environmental causes, rather than to some enduring personality trait. 17
advanced empathy: A later stage in client-centered therapy in which the therapist gradually begins to suggest what might be causing the client’s problems, while still showing a deep understanding of the client’s point of view. 16
afferent pathways: Nerve pathways leading toward the central nervous system. 3
age-thirty crisis: A time when people in their early thirties sometimes feel that any unsatisfactory aspect of their lives must be rectified immediately; otherwise, it will be too late to do so. 10
aggression: Behavior that is directed toward intentionally injuring another person who does not wish to be hurt. 18
agoraphobia: An intense fear of being in places that are hard to escape from quickly or without embarrassment, or where help would not be readily available. 15
alcohol abusers: People who are not alcoholic (alcohol-dependent) but who do have a drinking problem. 15
alcohol dependence: Any problem involving alcohol; psychological and physical addiction to alcohol. 15
algorithm: A precisely stated set of rules for solving problems of a particular kind. 8
alpha waves: Moderately slow brain waves that occur when a person relaxes with eyes closed. 5
altruism: Unselfish concern for others. 18
amplitude: A measure of light intensity as determined by the variation between the “peak” and “trough” of the light wave. For sound waves, the intensity as measured by the distance of the wave’s peaks and valleys from a baseline of zero; amplitude determines loudness. 4
amygdala: One of the three interrelated structures of the limbic system; the others are the septum and hippocampus. 3
anal stage: According to Freud, the second psychosexual stage (occurring during the second year of life), during which bowel control is accomplished and pleasure focused on the function of elimination. 13
anorexia nervosa: A condition in which a person becomes so obsessed with the subject of weight control that she (it is usually a teenage girl) literally starves herself to death in an attempt to shed pounds. 12
anterograde amnesia: A form of amnesia that affects memory only for new events and information, not for things stored in the past. 7
antianxiety drugs: Commonly known as minor tranquilizers, they sedate, that is, produce a calming effect. 16
antidepressant drugs: Mood-regulating drugs effective in treating certain types of depression. 15, 16
antipsychotic drugs: Any major tranquilizer used to alleviate extreme agitation and hyperactivity in psychotic patients. 16
antisocial personality (sociopath): A person with a history of antisocial acts beginning in childhood or adolescence and continuing into adulthood. These people act on impulse without considering others, with no guilt or remorse. 15
anxiety: According to Freud, a state of psychic distress that results when the ego is losing its struggle to reconcile the demands of the id, the superego, and reality. 13
anxiety disorders: A group of mental disorders characterized by feelings of vulnerability, apprehension, or fear. 15
anxious attachment: The type of bond between infant and caregiver characterized by the expectation that the caregiver will be inaccessible at times and somewhat unresponsive and ineffective. 10
assimilation: According to Piaget, a mental process that involves the incorporation of new information into old ways of thinking and behaving. 9
associative learning: Learning that certain events are connected with one another. 6
attitude: A disposition to respond favorably or unfavorably toward a person, thing, event, place, idea, or situation. 17
attitude object: The target of an attitude; that person, thing, event, idea, or situation that we have a disposition to evaluate in a particular way. 17
auditory canal: The passageway that extends from the opening of the outer ear to the eardrum. 4
auditory nerve: The nerve that carries neural impulses, triggered by movement of hair cells, to the brain stem. From there the impulses ascend through the thalamus to the auditory cortex, where the perception of sound begins. 4
authoritarian: A parenting style, identified by Diana Baumrind, characterized by harsh controlling behavior, lack of responsiveness to a child’s wishes, and inflexible thinking. 10
authoritarian personality: An individual characterized by rigid adherence to conventional values, a preference for strong, antidemocratic leaders, and a fear and hatred of almost anyone who is different from oneself. 17
authoritative: A parenting style, identified by Diana Baumrind, characterized by responsiveness, coupled with firmness in setting limits, and flexibility in thinking. 10
autobiographical memories: Personal, individual memories that pertain to one’s own life. 7
automatic encoding: Memory encoding that happens effort-lessly. 7
autonomic nervous system: The division of the peripheral nervous system that controls the internal muscles (blood vessels, heart, intestines) and the glands. 3
availability heuristic: An approach people use to judge odds involving the assessment of the probability of an uncertain event to occur according to the ease with which past examples come to mind. 8
aversive conditioning: A therapeutic technique that attempts to reduce the frequency of deviant behavior by pairing an aversive stimulus with the undesired behavior. 6, 16
avoidance learning: A cause-and-effect relationship whereby learning takes place through avoiding the stimulus. It can be established through negative reinforcement. 6
axon: The long extension of a neuron that usually transmits impulses away from the cell body. 3