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 meaningful-
ness of the information to the individual.
Libido—life/sexual energy force of the id (according
to Freud).
Linguistic relativity hypothesis—Whorfian belief
that the language a person speaks guides and
determines their 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 unpre-
dictable (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
developmental changes by evaluating the same
group of people at different times in their lives.
Lucid dreaming—the ability to be aware of and
direct one’s dreams.
Magnetic resonance imaging (MRI)—more detailed
computerized 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 (clinical) depression—persistent and severe
feelings of sadness (dysphoria) and worthlessness
accompanied by changes in appetite, sleeping,
and behavior.
Maladaptive behavior—is behavior which is coun-
terproductive; interferes with one’s interaction in
society and a factor in mental illness.
Mandala—According to Jung, is 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 regu-
lates heart rhythm, blood flow, breathing rate,
digestion, 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.
Mental age—a measure of a your intellectual devel-
opment; the level of mental development relative
to others.
Mental retardation—intellectual deficiency charac-
terized by intelligence quotient at least two stan-
dard deviations below the mean and difficulty in
adapting to and coping with environmental
demands of independent living.
Mental set—tendency to apply problem-solving
methods 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—the systematic statistical method
for synthesizing the results of numerous research
studies dealing with the same variables.326 ❯ Glossary