Developmental psychology.pdf

Glossary 589
neurotransmitter substance A chemical discharged into
the synaptic space which influences the transmission of
nerve impulses. It acts on the membrane of adjacent
fibers, creating an excitatory or inhibitory condition by
causing the adjacent membrane to become depolarized
or more polarized. In the former case, a transmission
occurs; in the latter, the nerve is more resistant to firing.
See excitatory/inhibitory synapses.
neutral stimulus One which does not elicit the response in
question. A puff of air to the eyeball, for example, is a
neutral stimulus for salivation. It does not evoke the
salivary response automatically. Through repeated
presentations with a stimulus such as meat, it could
become a conditioned response for salivation. A puff of
air is not a neutral stimulus for the eyeblink, however; it
is an unconditioned stimulus in the case of the eyeblink.
See also conditioned stimulus and unconditioned
stimulus.
noise In signal detection theory, a term referring to
extraneous influences on a perceptual or sensory task.
In research on visual thresholds, for example, the
subject must distinguish extraneous visual influences
from the visual target.
nomothetic research (пб-muh-thet'-ik)'
Concerned with the discovery of general laws,
pertaining to groups of individuals. Much of
contemporary research in psychology involves
nomothetic studies. See also idiographic research.
nonauditory labyrinth The semicircular canals and
vestibule.
nondirective counseling See person-centered approach.
nonprocreative sex Sexual activity which does not have
the possibility of leading to further propagation of the
species; it is not fundamental to sexual intercourse. See
masturbation, sadism, masochism, exhibitionism, and
voyeurism.
nonverbal items Test questions which involve pictures,
blocks, puzzles, gestures, figures, and so forth, rather
than words.
noradrenalin (nor-uh-dren'-ul-un) A secretion of the adrenal
gland and apparently also of nerve endings in the
sympathetic nervous system. This hormone is involved
in the maintenance of normal blood pressure.
normal curve A symmetrical, bell-shaped distribution with
most scores clustering near the center and the rest
tapering off to two extremes; the so-called chance
distribution.
norm-referenced test A test in which each person's score
is evaluated in the context of others' performances.
Usually used for purposes of selection and for
identifying individual differences.
norms Empirically established standards. Sometimes
refers to normal, defined as average. See local norms.
no-trial learning In social learning theory, an instance in
which the correct response appears on the first trial.
Learning apparently has occurred through observation
of a model, and when the occasion arises, the observer
emits the proper response on the first attempt.
obesity The condition of being fat or corpulent.
objectivity The state or condition of being impartial. Also,
a condition which is generally observable; known and
agreed upon by others. See subjectivity.
object permanence In Piagetian psychology, the capacity
for memory. The child who has achieved object
permanence understands that a given object may
continue to exist even when it is not directly
experienced. A memory, idea, or view of the objecTVs
carried around in the head. The development of object
permanence is a necessary prelude to thinking, for
thinking requires symbolic manipulation.
obsession A thought which occurs over and over again,
often irrational in nature and involving anxiety.
obsessive-compulsive disorder An adjustment reaction
in which the individual is beset with unwanted but
recurring thoughts (obsessions) and/or ritualistic
behaviors (compulsions).
occipital lobe (ok-sip'-ut-ul) The area at the back of each
cerebral hemisphere, concerned primarily with vision
and related perceptual and associative functions.
Oedipus complex (ed'-i-pus) A Freudian term representing
the sexual attachment of a son for his mother, usually
regarded as repressed and disguised in various ways.
Also, it is assumed that the son will be jealous of the
father because the father can have intimacies with the
mother that the son is denied. See also Electra complex.
olfactory epithelium (Cl-fak'-tuh-ree ep-uh-thee'-lee-um)
Tissue in the nasal cavity, which contains the receptors
for smell.
olfactory sensitivity (ol-fak'tuh-ree) The sense of smell.
one-trial conditioning The view that a habit or response
pattern can be fully acquired on the first successful trial.
open-ended item In questionnaires, a question or item
which provides little structure for the response. The
subject is given considerable latitude. For example; the
item may state: "Describe your feelings about yourself."
See structured item.
operant behavior Any response which produces certain
consequences—such as a food reward. It "operates"
on the environment. The eliciting stimulus cannot be
identified precisely, as it can in respondent behavior.
The operant response is said to be emitted rather than
elicited.
operant conditioning A type of conditioning which
involves the modification of an operant response
through reinforcements A response which the organism
emits is reinforced in certain ways, in accordance with
certain schedules, and resulting changes in its rate of
occurrence are studied. The rat's pressing a lever and
the pigeon's pecking a disk are widely studied operants.
The reinforcement is usually food, although a secondary
reinforcer, such as a click previously associated with
food, may be used. See also approximations, method of
and reinforcement.
operant learning See operant conditioning.
operant response (R o
) In operant conditioning, an overt
response; a response which is voluntarily emitted by the
individual. Reading a book, riding a bicycle, and
climbing a mountain are all operant responses; the
individual is operating on the environment.