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dark adaptation:

the gradual process
through which the eyes adjust from a change in illumination from light
to low light intensity.



Darwin (
1809-1882):
a hugely influential naturalist, who proposed that all species evolve
through natural selection so that traits that enhance survival are
passed on.

daydream: a
visionary fantasy experienced while awake, especially one of happy,
pleasant thoughts, hopes, or ambitions.


debriefing:
an

ethical
procedure that occurs at the end of a study, whereby
participants are given as much information as possible about the study,
are given the option to discuss  their experience of the study, to
ensure that
participants leave the
experiment in the same
emotional
state as they entered.


decay:

the loss of information in
memory over a long period of time.



deception:

in research, the
intentional misleading and misinforming of
participants with regard to
the aim of the study.



decibels (dB):
a
measure of volume (sound intensity) .decision-making:
reasoning that involves considering and choosing different
options.


declarative knowledge:

memory
for facts (semantic
knowledge
) and events (episodic
knowledge
).




deduction/deductive
reasoning
:

the logical process of drawing a particular conclusion from
a set of general principles.



defence mechanism:


psychological
strategies as part of
Freudian

psychoanalytic

theory, that are used to distort or deny
reality, in order to cope with

anxiety
and/or a situation which an individual feels is
difficult to cope with.



deindividuation:

a

process
through which group members cease to view themselves as
individuals. Individual identity is replaced with
identification with a group.



delinquency:

criminal/antisocial activity.


delusion:
unfounded and irrational beliefs held despite contrary
evidence. Characteristic of
mental disorders such as

schizophreni
a,
can be manifested in delusions of grandeur (believing that
one is famous or powerful) or delusions of persecution
(believing that one is being chased or followed).



demand characteristic:

cues in an
experiment that reveal information to
participants about the aim and expected outcome, thereby
influencing their behavior and subsequently confounding the
results.  



dementia:

disorder
characterised by considerable deterioration in
cognitive
function, for instance in loss of
memory. Different types of
dementia include

corticial
dementias (e.g.
Alzheimers disease
) and sub-cortical dementias
(e.g.
Huntingtons
disease
).


demographic:

a

socioeconomic
or similar factor that defines a certain
group or area.


dendrites:

branched
fibres at the end of the cell body of a

neuron
that receive incoming impulses


denial:

a
defence mechanism

, whereby
an individual may denies or rejects some aspect of reality.



deoxyribonucleic acid
(DNA):

the
molecule which forms basis of heredity. DNA holds all
genetic information on the
chromosomes.


dependent
personality disorder:

a form of


personality disorder
, whereby an individual is
heavily reliant upon others and demonstrates feelings of
inadequacy and helplessness when alone.

dependent variable (DV):
in an
experiment, the values of the variable that
change as a result of manipulation of the

independent variable
.



depression
(unipolar disorder):

a type of
mood disorder
, characterised by persistent feelings of great
sadness, hopelessness, worthlessness,
guilt and a loss of
interest in activities.



deprivation:

a condition of having too
little of something.


depth/distance
(visual) perception:

the
capability to view the world three-dimensionally, utilising
monocular and binocular cues to appraise depth and distance
between objects.


descriptive statistics:
the description and summation of sets of scores in statistics.
 


determinism:

the
assumption
that all behaviour has specific causes.



developmental psychology:

also known as human development. It is
the scientific study of the processes which underlie and control growth
and change in behaviour over time.


deviant behavior:
behavior that is a recognised
violation of social norms.?



diagnosis:

the
identification and classification of a

psychological disorder
.



Diagnostic and
Statistical Manual (DSM):

a
multi-axial manual used for the
classification, definition and description of
mental health
disorders
.


diathesis-stress model:

an explanation of
mental disorders based on a combination of
genetic vulnerability (diathesis) and environmental
influences.

dichotic listening:

utilised in attention research, whereby a different auditory
message is simultaneously presented to each ear.
Participants are required to repeat one of the messages
whilst ignoring the other.


diencephalon:

a part of
the
forebrain, containing the

thalamus
and the

hypothalamus
.



diffusion of
responsibility:

occurs
in groups when an individual feels less responsibility
because accountability is diffused amongst the group.
Evident in emergency situations, whereby the larger the
number of bystanders, the less responsibility each bystander
feels.



digit span:

a test of


short-term memory
, whereby
participants are
presented with a series of digits and asked to repeat them.
Average digit span is 7 +/- 2.



directional hypothesis:
states which of the two condition
means will be larger, most often used,

one tailed T-test
.



discovery learning:
a

Piagetian
belief that children learn through
self-discovery, aided by a teacher providing suitable
materials, thereby stimulating

intrinsic satisfaction
.



discrete variable:

measurement using of a discrete category (eg. Gender) as
opposed to a continuous score (e.g height, weight,
intelligence).



discrimination:

unequal and unlawful
treatment based upon race, colour, creed, religion, sex,
national origin, age, disability, veteran status, or

sexual orientation
.



disengagement theory:

mutual process of disengagement in activities expected by
the individual and by society.


disorganised speech:

one of the

positive symptoms
of

schizophrenia
, a disturbance whereby speech
is disjointed and incoherent.  



displacement:

forgetting
in

short-term memory
, as a result of to new incoming
information replacing the previous contents



dispositional
attribution:

when
behavior is attributed to internal factors that are directly
controllable by a person, e.g. an individuals effort or
ability, as opposed to external factors (situational
attributions
), such as the weather or bad luck.



dissociative disorder
:
Is a condition, often caused by

trauma
, in which a person disconnects from a full
awareness of self, time, or external circumstances as a
defence against unpleasant realities or

memories
.


distal cause:
a factor which has an indirect effect on behaviour, such as
previous experiences in similar situations.


divided attention:
the
ability to divide our attentional processing between more
than one task.



dizygotic twins (non-identical
twins):

twins that develop from different

zygotes
(eggs) and only share about fifty percent of
their

DNA
.



door-in-the-face
technique:

a technique
used to induce

compliance
, whereby individuals are first
asked a large favour, followed by a smaller favour, which is
more likely to be followed.



dopamine:

a chemical


neurotransmitter
in the
brain, important for
learning and the experience of pleasure and reward.



dopamine hypothesis:

argues that

schizophrenia

is based on over-activity of

synapses
that depend on

dopamine
.



double-bind theory:
a
theory of

schizophrenia
proposed by
Bateson, which argues that
faulty communication patterns within the family contribute
to the onset of

schizophrenia
.

double-blind design: a form of experimental control, whereby both the subject and
experimenter are kept uninformed about the purpose of the
experiment, to reduce any forms of bias (in particular,
experimenter

bias
).



Down’s syndrome:

a
chromosomal disorder that is characterised by low

IQ
levels.


dreaming:

a stage of sleep typified by the experience of visual
imagery and

rapid eye movements
(REM).


drive reduction theory
(of motivation):

Hull’s proposal that all behaviour is motivated and that

motivation
stems from the satisfaction of

homeostatic
drives (e.g. hunger and thirst).
Stimuli (e.g. food and water) that decreases the drives
subsequently reinforce the behaviour that led to them.


drug treatments:

treatment of
psychological disorders that are based on biological
explanations of
abnormal behavior. Treatment includes
anti-anxiety drugs,
anti-depressant
drugs and anti-bipolar drugs.


dysfunctional:

functioning incorrectly or
abnormally.



dyslexia:

‘developmental dyslexia’ is used to explain difficulties
with written and spoken language (across differing levels of
intellect) that occurs as a result of development, whilst
acquired dyslexia?occurs as a result of a stroke or
similar injury, whereby language skills are impaired.

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