G-5 GloSSARy
mental set A tendency to solve problems using procedures that worked
before on similar problems.
meta-analysis A set of techniques for combining and analyzing data
from a number of related studies to determine the explanatory strength
of a particular independent variable.
metacognition The knowledge or awareness of one’s own cognitive pro-
cesses and the ability to monitor and control those processes.
mirror neurons Brain cells that fire when a person or animal observes
another carrying out an action; these neurons appear to be involved in
empathy, imitation, and reading emotions.
mnemonics [neh-MoN-iks] Strategies and tricks for improving memory,
such as the use of a verse or a formula.
mode A measure of central tendency; the most frequently occurring
score in a distribution.
monocular cues Visual cues to depth or distance that can be used by
one eye alone.
mood-congruent memory The tendency to remember experiences that
are consistent with one’s current mood and overlook or forget experi-
ences that are not.
motivation An inferred process within a person or animal that causes
movement either toward a goal or away from an unpleasant situation.
MRI (magnetic resonance imaging) A method for studying body and
brain tissue, using magnetic fields and special radio receivers. (See also:
fMRI.)
myelin sheath A fatty insulation that may surround the axon of a neuron.
narcolepsy A sleep disorder involving sudden and unpredictable daytime
attacks of sleepiness or lapses into REM sleep.
negative correlation An association between increases in one variable
and decreases in another.
negative reinforcement A reinforcement procedure in which a response
is followed by the removal, delay, or decrease in intensity of an unpleas-
ant stimulus; as a result, the response becomes stronger or more likely
to occur.
nerve A bundle of nerve fibers (axons and sometimes dendrites) in the
peripheral nervous system.
neurogenesis The production of new neurons from immature stem cells.
neuromodulators Neurochemicals that modulate the functioning of neu-
rons and neurotransmitters.
neurons Cells that conduct electrochemical signals; the basic unit of the
nervous system; also called nerve cells.
neurotransmitter A chemical substance that is released by a transmitting
neuron at the synapse and that alters the activity of a receiving neuron.
nonconscious processes Mental processes occurring outside of and not
available to conscious awareness.
nonshared environment Unique aspects of a person’s environment and
experience that are not shared with family members.
normal curve A symmetrical, bell-shaped frequency polygon represent-
ing a normal distribution.
normal distribution A theoretical frequency distribution having certain
special characteristics. For example, the distribution is symmetrical; the
mean, mode, and median all have the same value; and the farther a score
is from the mean, the less the likelihood of obtaining it.
norms In test construction, established standards of performance.
norms (social) Rules that regulate social life, including explicit laws and
implicit cultural conventions.
null hypothesis An assertion that the independent variable in a study
will have no effect on the dependent variable.
object permanence The understanding, which develops throughout the
first year, that an object continues to exist even when you cannot see it
or touch it.
objective tests (inventories) Standardized questionnaires requiring writ-
ten responses; they typically include scales on which people are asked
to rate themselves.kinesthesis [KIN-es-THEE-sis] The sense of body position and move-
ment of body parts; also called kinesthesia.
language A system that combines meaningless elements such as sounds
or gestures to form structured utterances that convey meaning.
latent learning A form of learning that is not immediately expressed in
an overt response; it occurs without obvious reinforcement.
lateralization Specialization of the two cerebral hemispheres for particu-
lar operations.
learning A relatively permanent change in behavior (or behavioral poten-
tial) due to experience.
learning perspective A psychological approach that emphasizes how
the environment and experience affect a person’s or animal’s actions; it
includes behaviorism and social-cognitive learning theories.
libido (li-BEE-do) In psychoanalysis, the psychic energy that fuels the
life or sexual instincts of the id.
lithium carbonate A drug frequently given to people suffering from bipo-
lar disorder.
localization of function Specialization of particular brain areas for par-
ticular functions.
locus of control A general expectation about whether the results of your
actions are under your own control (internal locus) or beyond your control
(external locus).
longitudinal study A study in which individuals are followed and period-
ically reassessed over a period of time.
long-term memory (lTM) In the three-box model of memory, the mem-
ory system involved in the long-term storage of information.
long-term potentiation A long-lasting increase in the strength of synap-
tic responsiveness, thought to be a biological mechanism of long-term
memory.
loudness The dimension of auditory experience related to the intensity
of a pressure wave.
lucid dreams Dreams in which the dreamer is aware of dreaming.
maintenance rehearsal Rote repetition of material to maintain its avail-
ability in memory.
major depression A disorder marked by excessive sadness, loss of
interest in usual activities, feelings of worthlessness and hopelessness,
thoughts of suicide, and physical symptoms (such as fatigue and loss of
appetite).
mastery (learning) goals Goals framed in terms of increasing one’s com-
petence and skills.
mean See arithmetic mean.
measure of central tendency A number intended to characterize an
entire set of data.
measure of variability A number that indicates how dispersed scores are
around the mean of the distribution.
median A measure of central tendency; the value at the midpoint of a
distribution of scores when the scores are ordered from highest to lowest.
medulla [muh-DUl-uh] A structure in the brain stem responsible for
certain automatic functions, such as breathing and heart rate.
melatonin A hormone, secreted by the pineal gland, that is involved in
the regulation of daily biological rhythms.
menarche [men-ARR-kee] The onset of menstruation during puberty.
menopause The cessation of menstruation and of the production of ova;
it is usually a gradual process lasting up to several years.
mental age (MA) A measure of mental development expressed in terms
of the average mental ability at a given age.
mental disorder Any behavior or emotional state that causes an individ-
ual great suffering, does not go away after a reasonable length of time, is
self-destructive, seriously impairs the person’s ability to work or get along
with others, or causes the person to endanger others or the community.
mental image A mental representation that mirrors or resembles the
thing it represents; mental images can occur in many and perhaps all
sensory modalities.