GloSSARy G-6phantom pain The experience of pain in a missing limb or other body part.
phobia An exaggerated, unrealistic fear of a specific situation, activity,
or object.
phrenology The now discredited theory that different brain areas account
for specific character and personality traits, which can be “read” from
bumps on the skull.
pitch The dimension of auditory experience related to the frequency of a
pressure wave; the height or depth of a tone.
pituitary gland A small endocrine gland at the base of the brain that
releases many hormones and regulates other endocrine glands.
placebo An inactive substance or fake treatment used as a control in an
experiment.
placebo effect The apparent success of a medication or treatment
because of the patient’s expectations or hopes rather than to the drug or
treatment itself.
plasticity The brain’s ability to change and adapt in response to experi-
ence, by reorganizing or growing new neural connections.
pons A structure in the brain stem involved in, among other things,
sleeping, waking, and dreaming.
positive correlation An association between increases in one variable
and increases in another, or between decreases in one and decreases
in the other.
positive reinforcement A reinforcement procedure in which a response is
followed by the presentation of, or increase in intensity of, a reinforcing
stimulus; as a result, the response becomes stronger or more likely to occur.
postdecision dissonance In the theory of cognitive dissonance, tension
that occurs when you believe you may have made a bad decision.
posttraumatic stress disorder (PTSD) An anxiety disorder in which a
person who has experienced a traumatic or life-threatening event has
long-lasting symptoms such as recurrent, intrusive thoughts, flashbacks,
nightmares, and increased physiological arousal.
power assertion A method of child rearing in which the parent uses pun-
ishment and authority to correct the child’s misbehavior.
prejudice A strong, unreasonable dislike or hatred of a group, based on
a negative stereotype.
primary control An effort to modify reality by changing other people, the
situation, or events; a “fighting back” philosophy.
primary punisher A stimulus that is inherently punishing; an example
is electric shock.
primary reinforcer A stimulus that is inherently reinforcing, typically sat-
isfying a physiological need; an example is food.
priming A method for measuring implicit memory in which a person
reads or listens to information and is later tested to see whether the
information affects performance on another type of task.
principle of falsifiability The principle that a scientific theory must
make predictions that are specific enough to expose the theory to the
possibility of disconfirmation.
proactive interference Forgetting that occurs when previously stored
material interferes with the ability to remember similar, more recently
learned material.
procedural memories Memories for the performance of actions or skills
(“knowing how”).
projective tests Psychological tests used to infer a person’s motives,
conflicts, and unconscious dynamics on the basis of the person’s inter-
pretations of ambiguous stimuli.
proposition A unit of meaning that is made up of concepts and expresses
a single idea.
prototype An especially representative example of a concept.
psychedelic drugs Consciousness-altering drugs that produce hallucina-
tions, change thought processes, or disrupt the normal perception of
time and space.
psychoactive drugs Drugs capable of influencing perception, mood, cog-
nition, or behavior.object-relations school A psychodynamic approach that emphasizes the
importance of the infant’s first two years of life and the baby’s formative
relationships, especially with the mother.
observational learning A process in which an individual learns new
responses by observing the behavior of another (a model) rather than
through direct experience; sometimes called vicarious conditioning.
observational study A study in which the researcher carefully and sys-
tematically observes and records behavior without interfering with the
behavior; it may involve either naturalistic or laboratory observation.
obsessive-compulsive disorder (oCD) A disorder in which a person feels
trapped in repetitive, persistent thoughts (obsessions) and repetitive,
ritualized behaviors (compulsions) designed to reduce anxiety.
occipital [ahk-SIP-uh-tuhl] lobes Lobes at the lower back part of the
brain’s cerebral cortex; they contain areas that receive visual information.
oedipus complex In psychoanalysis, a conflict occurring in the phallic
(Oedipal) stage, in which a child desires the parent of the other sex and
views the same-sex parent as a rival.
operant conditioning The process by which a response becomes more
likely to occur or less so, depending on its consequences.
operational definition A precise definition of a term in a hypothesis,
which specifies the operations for observing and measuring the process
or phenomenon being defined.
opiates Drugs, derived from the opium poppy, that relieve pain and com-
monly produce euphoria.
opponent-process theory A theory of color perception that assumes that
the visual system treats pairs of colors as opposing or antagonistic.
organ of Corti [CoRE-tee] A structure in the cochlea containing hair
cells that serve as the receptors for hearing.
oxytocin A hormone, secreted by the pituitary gland, that stimulates
uterine contractions during childbirth, facilitates the ejection of milk
during nursing, and seems to promote, in both sexes, attachment and
trust in relationships.
panic disorder An anxiety disorder in which a person experiences recur-
ring panic attacks, periods of intense fear, and feelings of impending
doom or death, accompanied by physiological symptoms such as rapid
heart rate and dizziness.
papillae [pa-PIll-ee] Knoblike elevations on the tongue, containing the
taste buds. (Singular: papilla.)
parallel distributed processing (PDP) model A model of memory in
which knowledge is represented as connections among thousands of
interact-ing processing units, distributed in a vast network, and all oper-
ating in parallel. Also called a connectionist model.
parasympathetic nervous system The subdivision of the autonomic ner-
vous system that operates during relaxed states and that conserves energy.
parietal [puh-RyE-uh-tuhl] lobes Lobes at the top of the brain’s cerebral
cortex; they contain areas that receive information on pressure, pain,
touch, and temperature, and that are involved in attention and awareness
of spatial relationships.
percentile score A score that indicates the percentage of people who
scored at or below a given raw score; also called centile rank.
perception The process by which the brain organizes and interprets sen-
sory information.
perceptual constancy The accurate perception of objects as stable or
unchanged despite changes in the sensory patterns they produce.
perceptual set A habitual way of perceiving, based on expectations.
performance goals Goals framed in terms of performing well in front of
others, being judged favorably, and avoiding criticism.
peripheral nervous system (PNS) All portions of the nervous system out-
side the brain and spinal cord; it includes sensory and motor nerves.
personality A distinctive and relatively stable pattern of behavior,
thoughts, motives, and emotions that characterizes an individual.
PET scan (positron-emission tomography) A method for analyzing bio-
chemical activity in the brain, for example by using injections of a glu-
coselike substance containing a radioactive element.