IQ Glossary

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  

Declarative Memory
Declarative memory is the aspect of memory that stores facts and events. It applies to standard textbook learning and knowledge. It is based on pairing the stimulus and the correct response. For example, the question "What is the capital of Sierra Leone?" is paired with the answer "Freetown". The name declarative comes from the fact that we can explicitly "ask" our brain to make a connection between a pair of stimuli. Declarative memory is subject to forgetting and requires repetition to last for years. Declarative memories are best established by using active recall combined with mnemonic techniques and spaced repetition.

Deductive Reasoning
In traditional Aristotelian logic, deductive reasoning is inference in which the conclusion is of lesser or equal generality than the premises, as opposed to inductive reasoning, where the conclusion is of greater generality than the premises. Other theories of logic define deductive reasoning as inference in which the conclusion is just as certain as the premises, as opposed to inductive reasoning, where the conclusion can have less certainty than the premises. In both approaches, the conclusion of a deductive inference is necessitated by the premises: the premises can't be true while the conclusion is false. (In Aristotelian logic, the premises in inductive reasoning can also be related in this way to the conclusion.)

Degrees Of Freedom
The term "degrees of freedom" is used in three different branches of science: in physics and physical chemistry, in mechanical and aerospace engineering, and in statistics. The three usages are linked historically and through the underlying mathematics through the concept of dimensionality, but they are not identical.

Delusion
A delusion is commonly defined as a false belief, and is used in everyday language to describe a belief that is either false, fanciful or derived from deception. In psychiatry, the definition is necessarily more precise and implies that the belief is pathological (the result of an illness or illness process).

Dementia
Dementia (from Latin demens) is progressive decline in cognitive function due to damage or disease in the brain beyond what might be expected from normal aging. Particularly affected areas may be memory, attention, language and problem solving, although particularly in the later stages of the condition, affected persons may be disoriented in time (not knowing what day, week, month or year it is), place (not knowing where they are) and person (not knowing who they are). Symptoms of dementia can be classified as either reversible or irreversible depending upon the etiology of the disease, although dementia, by definition, is irreversible and will eventually result in death. Dementia is a non-specific term that encompasses many disease processes just as fever is attributable to many etiologies.

Dementia With Lewy Bodies
Dementia with Lewy bodies is the second most frequent cause of hospitalization for dementia, after Alzheimer's disease. Current estimates are that about 60 to 75% of diagnosed dementias are of the Alzheimer's and mixed (Alzheimer's and vascular dementia) type, 10 to 15% are Lewy Bodies type, with the remaining types being of an entire spectrum of dementias including frontotemporal, Pick's disease, alcoholic dementia, pure vascular dementia, etc.

Dendrite
In biology, a dendrite is a slender, typically branched projection of a nerve cell, or "neuron," which conducts the electrical stimulation received from other cells to the body or soma of the cell from which it projects. This stimulation arrives through synapses, which typically are located near the tips of the dendrites and away from the soma.

Developmental Psycholog
Developmental psychology is the scientific study of age related behavioral changes which occur as a child grows up. This field examines change across a broad range of topics including: motor skills, problem solving abilities, conceptual understanding, acquisition of language, moral understanding, and identity formation.

Disorientation
Orientation is a function of the mind involving awareness of three dimensions: (1) time, (2) place and (3) person. Problems with orientation lead to disorientation, and can be due to various conditions, from delirium to intoxication. Typically, disorientation is first in time, then in place and finally in person.

Dissociation
The Diagnostic and Statistical Manual of Mental Disorders considers symptoms such as depersonalization, derealization, and psychogenic amnesia as core features of dissociation. However, in the normal population mild dissociative experiences are highly prevalent, with 80% to 90% of the respondents indicating that they experience dissociative experiences at least some of the time.

Dopamine
Dopamine is a chemical naturally produced in the body. In the brain, dopamine functions as a neurotransmitter, activating dopamine receptors. Dopamine is also a neurohormone released by the hypothalamus. Its main function as a hormone is to inhibit the release of prolactin from the anterior lobe of the pituitary.

Double Blind Study
Double-blind describes an especially stringent way of conducting an experiment, usually on human subjects, in attempt to eliminate subjective bias on the part of both experimental subjects and the experimenters.