Defense mechanisms

In psychoanalytic theory, the ego’s protective methods of reducing anxiety by unconsciously distorting reality

 

Deindividuation

The loss of self-awareness and self-restraint occurring in group situations that foster arousal and anonymity

 

Déjà vu

That eerie sense that “I’ve experienced this before”. Cues form the current situation may subconsciously trigger retrieval of an earlier experience

 

Delta waves

The large, slow brain waves associated with deep sleep

 

Delusions

False beliefs, often of persecution or grandeur, that may accompany psychotic disorders

 

Dendrite

The bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body

 

Dependent variable

The experimental factor- in psychology, the behavior or mental process –that is being measured; the variable that may change in response to manipulations of the independent variable

 

Depressants

Drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions

 

Depth perception

The ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance

 

Developmental psychology

A branch of psychology that studies physical, cognitive, and social change throughout the life span

 

Difference threshold

The minimum difference that a person can detect two stimuli. We experience the difference threshold as a just noticeable difference

Discrimination

In classical conditioning, the learned ability to distinguish between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus

 

Displacement

Defense mechanism that shifts sexual or aggressive impulses toward a more acceptable or less threatening object or person, as when redirecting anger toward a safer outlet

 

Dissociation

A split in consciousness, which allows some thoughts and behaviors to occur simultaneously with others

 

Dissociative disorders

Disorder in which conscious awareness becomes separated from previous memories, thoughts, or feelings

 

Dissociative identity disorder

A rare dissociative disorder in which a person exhibits two or more distinct and alternating personalities

 

DNA (deoxyribonucleic acid)

A complex molecule containing the genetic information that makes up the chromosomes A DNA molecule has two strands – forming a double helix – held together by bonds between pairs of nucleotides

 

Double-blind procedure

An experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or placebo. Commonly used in drug evaluation studies

 

Down syndrome

A condition of retardation and associated physical disorders caused by an extra chromosome in one’s genetic makeup

 

Dream

A sequence of images, emotions, and thoughts passing through a sleeping person’s mind. Dreams are notable for their hallucinatory imagery, discontinuities, and incongruities, and for the dreamer’s delusional acceptance of the content and later difficulties remembering it

 

Drive-reduction theory

The idea that a physiological need creates an aroused tension state (a drive) that motivates an organism to satisfy the need

 

DSM-IV

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, a widely used system for classifying psychological disorders

 

Dualism

The presumption that mind and body are two distinct entities that interact