Glossary ❮ 337Inhibitory neurotransmitter—chemical secreted at
terminal button that reduces or prevents neural
impulses in the postsynaptic neuron.
Insight learning—the sudden appearance (often
creative) or awareness of a solution to a problem.
Insomnia—the inability to fall asleep and/or stay asleep.
Instinct—inherited, complex automatic species-
specific behavior.
Instinct theory—theory of motivation that physical
and mental instincts such as curiosity and fearful-
ness cause us to act.
Instinctive drift—the tendency of an animal to
revert to instinctive behavior which interferes with
learning.
Instrumental aggression—hostile act intended to
achieve some goal.
Instrumental learning—learning that occurs when
a response is weakened or strengthened by its
consequence.
Intellectual disability—neurodevelopmental condi-
tion ranging from mild to profound, also called
intellectual developmental disorder, characterized
by intelligence quotient below 70 and difficulty
in adapting to and coping with environmental
demands of independent living. Previously called
mental retardation.
Intellectualization—Freudian defense mechanism
that involves reducing anxiety by reacting to emo-
tional situations in a detached, unemotional way.
Intelligence—the global capacity to act purposefully,
to think rationally, and to deal effectively with the
environment.
Intelligence quotient (IQ)—mental age divided by
chronological age multiplied by 100.
Interference theory—learning some items may pre-
vent retrieving others, especially when the items
are similar.
Intermittent reinforcement—the occasional rein-
forcement of a particular behavior; produces
response that is more resistant to extinction than
continuous reinforcement.
Internal locus of control—based on Julian Rotter’s
research, the belief that you control what happens
to you through your own individual effort and
behavior.
Internalization—the process of absorbing informa-
tion from a specified social environmental context
(according to Lev Vygotsky).
Interneuron—nerve cell in the CNS that transmits
impulses between sensory and motor neurons.
Intimacy vs. isolation—In Erikson’s theory, the
ability to establish close and loving relationships
is the primary task of late adolescence and early
adulthood.Intrinsic motivation—a desire to perform an activ-
ity for its own sake rather than for an external
reward.
Introvert—Jungian term for the opposite of extra-
vert; a person with a tendency to get energy from
individual pursuits; a person with the trait of shy-
ness, the desire to avoid large groups, and who pre-
fers to pay attention to private mental experiences
(according to Eysenck).
Iris—colored muscle surrounding the pupil that
regulates the size of the pupil’s opening.
James-Lange theory—the conscious experience of
emotion results from your awareness of autonomic
arousal and comes only after your behavioral
response to situations.
Jigsaw classroom—Aronson and Gonzales devised
learning experience where students of diverse
backgrounds are first placed in expert groups
where they learn one part of lesson, and then share
that information in jigsaw groups made up of one
student from each of the expert groups. Students
are dependent upon each other; self-esteem and
achievement of “poorer” students improves, and
former stereotypes are diminished.
Just noticeable difference (jnd)—experience of the
difference threshold.
Kinesthesis—body sense that provides information
about the position and movement of individual
parts of the body with receptors in muscles, ten-
dons, and joints.
Klinefelter’s syndrome—males with XXY sex
chromosomes.
Language—communication system based on words
and grammar; spoken, written, or gestured words
and the way they are combined to communicate
meaning.
Latency stage—fourth of the Freudian stages of
development (6–12); sublimation of sexual plea-
sure into school work and other activities; if libido
fixates here, the result is feelings of inferiority and
poor self-concept.
Latent content—according to Freud, the underlying
meaning of a dream.
Latent learning—learning when no apparent rewards
are present; it becomes apparent only when there is
an incentive to demonstrate it.
Law of Effect—Thorndike’s observation that behav-
iors followed by rewards are strengthened and
behaviors followed by punishment are weakened.
Learning principle that behavior is acquired by
virtue of its consequences.
Learned helplessness—the feeling of futility and
passive resignation that results from inability to
avoid repeated aversive events.BM.indd 337 27-05-2018 15:32:47