338 ❯ GlossaryLearning—a relatively permanent change in behavior
as a result of experience.
Lens—structure in the eye behind the pupil that
changes shape, becoming more spherical or flatter,
to focus incoming rays into an image on the light-
sensitive retina.
Lesions—interruptions in tissue that result from
destruction of tissue by injury, tumors, scarring;
enables more systematic study of the loss of func-
tion when tissue loss results from surgical cutting
or removal (also called ablation), or destruction by
chemical applications.
Levels of processing theory or semantic network
theory—ability to form memories depends upon
the depth of the processing and the meaningfulness
of the information to the individual.
Libido—life/sexual energy force of the id (according
to Freud).
Linguistic relativity hypothesis—Whorf’s belief
that the language you speak guides and determines
your thinking; largely discredited.
Lithium carbonate—the drug treatment of choice
for bipolar disorder; it reduces levels of certain
neurotransmitters and decreases the strength of
neural firing.
Locus of control—the degree to which we expect
that a reinforcement or outcome of our behavior is
contingent on our own behavior or personal char-
acteristics (internal locus of control) as opposed to
the degree to which we expect that a reinforcement
or outcome of our behavior is a function of luck or
fate, is under the control of others, or is unpredict-
able (external locus of control).
Long-term memory (LTM)—the relatively permanent
and unlimited capacity memory system into which
information from short-term memory may pass.
Long-term potentiation (LTP)—an increase in a
synapse’s firing potential after brief, rapid stimula-
tion and possibly the neural basis for learning and
memory.
Longitudinal research—a method of assessing devel-
opmental changes by evaluating the same group of
people at different times in their lives.
Lucid dreaming—the ability to be aware of and
direct your dreams.
Magnetic resonance imaging (MRI)—detailed com-
puterized images using a magnetic field and pulses
of radio waves that cause emission of signals that
depend upon the density of tissue.
Maintenance rehearsal—repeating a given item over
and over again extends your short-term memory;
usually limited to about 20 seconds.
Major depressive disorder—characterized by persis-
tent and severe feelings of sadness (dysphoria) andworthlessness accompanied by changes in appetite,
sleeping, and behavior.
Maladaptive behavior—behavior which is coun-
terproductive; interferes with one’s interaction in
society, and is a factor in mental illness.
Mandala—According to Jung, a type of magical
circle symbolizing the self archetype in the collec-
tive unconscious.
Mania—excessive emotional arousal (euphoria) and
wild, exuberant, unrealistic activity.
Manifest content—according to Freud, the remem-
bered story line of a dream.
Maturation—the biological growth processes that
bring about orderly changes in behavior, thought,
or physical growth; relatively unaffected by
experience (nature argument).
Mean—the arithmetic average of a set of scores.
Median—the middle score when a set of data is
ordered by size.
Medulla oblongata—part of brainstem that regulates
heart rhythm, blood flow, breathing rate, diges-
tion, vomiting.
Memory—human capacity to register, retain, and
retrieve information over time; the persistence of
learning.
Menarche—first menstrual period at about age 12^1 / 2 ;
marks female fertility.
Menopause—the cessation of the ability to repro-
duce accompanied by a decrease in production of
female sex hormones at about age 50.
Mental age—a measure of your intellectual develop-
ment; the level of mental development relative to
others.
Mental retardation—intellectual deficiency char-
acterized by intelligence quotient at least two
standard deviations below the mean and difficulty
in adapting to and coping with environmental
demands of independent living.
Mental set—tendency to apply problem-solving meth-
ods that have worked in the past rather than trying
new or different strategies to solve a new problem,
which may or may not help solve the problem.
Mere exposure effect—the formation of a positive
attitude toward a person, place, or thing based
solely on repeated exposure to that person, place,
or thing; often used in advertising as form of subtle
persuasion.
Mesomorph—one of three body types (domineer-
ing, aggressive, muscular) developed in Sheldon’s
personality theory that correlates personality traits
and physique.
Meta-analysis—systematic statistical method for
synthesizing the results of numerous research stud-
ies dealing with the same variables.BM.indd 338 27-05-2018 15:32:47