Glossary of Psychological Terms
Definitions of terms used in psychology, psychometric testing and occupational assessment, organised alphabetically.
Iconic store
A brief visual memory trace, lasting only a second or two, that preserves an initial impression of a visual stimulus. Compare with echoic store, its auditory equivalent.
Id
From the Latin for “it”: in Freud's structural model of personality, the component housing the deepest, most primitive unconscious drives, closely tied to the body's biological impulses. Governed by the pleasure principle, the id creates problems for the ego whenever its drives are blocked from expression.
Ideal self
The set of values, standards and qualities a person holds for their own self and strives to live up to, whether or not they currently match that ideal.
Idée fixe
French for “fixed idea”: a persistent, obsessive idea or belief that remains unshaken by contradictory evidence or argument.
Identical twins
See monozygotic twins — twins developing from a single fertilised egg, sharing identical genetic material.
Identification
In general use, recognising the identity or nature of someone or something. In psychoanalysis, specifically, the unconscious process of adopting the attitudes, values or behaviours of a person with whom one shares a strong emotional bond, such as a parent.
Identity
The essential, relatively unchanging characteristics that constitute a person's basic sense of unity and continuity as themselves, especially their self-image.
Identity crisis
The acute experience of feeling that one's sense of identity and self have lost their normal stability and continuity, leaving a person disoriented and struggling to recognise or define themselves — a concept central to Erik Erikson's developmental theory.
Identity formation
The central task of the fifth of Erik Erikson's eight psychosocial stages, occurring during adolescence, in which the individual must work out and consolidate their own personal identity.
Idiographic
An approach within psychology that emphasises the uniqueness of the individual case rather than seeking general laws that apply across people. Compare with nomothetic, the search for broad, generalisable principles.
Idiot savant
An older French-derived term, now considered outdated (savant syndrome is the preferred modern term), for a person with an intellectual disability who nonetheless possesses an extraordinary, isolated ability in one specific domain, often music, drawing, memory or calculation — a combination that remains only partially understood.
Illusion
A mistaken perception, arising either from physical causes (as in an optical illusion) or psychological causes (as in a hallucination, though the two are distinguished by whether an external stimulus is actually present).
Imageless thought
A thought, or sequence of thought, occurring with no accompanying mental image or sensory content. Whether such thought genuinely exists has been debated since antiquity; most modern psychologists accept that it does.
Imitation
Copying another person's behaviour, whether as a deliberate, conscious act or an unconscious one. See also: modelling.
Immanent justice
The belief that wrongdoing is inevitably followed by punishment — that even undetected misdeeds will eventually be met with retribution, such as an accident or run of bad luck, imposed by some higher power. According to Piaget, this kind of thinking is typical of egocentric children below around age 8.
Immunisation
See inoculation, in its social-psychological sense of building resistance to persuasion through prior exposure to a weaker version of an opposing argument.
Implicit memory
Memory for previously learned material or skills that a person is not consciously aware of possessing — unlike explicit memory, implicit memory is often substantially preserved in people with amnesia.
Implicit personality theory
The largely unquestioned assumptions people rely on when judging another person's personality — specifically, which traits tend to be assumed to go together. For example, “warm” is commonly assumed to accompany “outgoing,” “sociable” and “good-humoured,” while “cold” is assumed to accompany “withdrawn,” “reserved” and “humourless.”
Impression formation
The process of building an overall judgement of another person by integrating the various pieces of information available about them. See also: impression management.
Impression management
A concept associated with Canadian sociologist Erving Goffman, describing the deliberate effort to present oneself to others in a way calculated to produce a particular, controllable or predictable reaction from them.
Inappropriate affect
An emotional response markedly out of step with the demands of a situation — for example, laughing at a tragic event — often regarded as a symptom of psychosis.
Incidental learning
Learning that occurs without any deliberate, conscious effort — for example, picking up the names of shops passed regularly on the way to a bus stop.
Incremental learning
Learning that proceeds through a series of small, regular, orderly steps, rather than arriving through sudden flashes of insight.
Independent variable
In an experiment, the variable that is deliberately manipulated by the researcher and whose changes form the basis for predicting changes in the dependent variable, rather than depending on any other variable itself. See also: experimental variable.
Individual differences
The systematic comparison of people's characteristics and performance — particularly, historically, intelligence and intelligence test scores, though the field now spans personality, ability and other psychological traits.
Inductive reasoning
A form of reasoning that infers general principles from a set of specific observed cases. Compare with deductive reasoning, which draws specific conclusions from general premises.
Industrial psychology
An older term for what is now generally called work psychology or organisational psychology, still in wide use, particularly in the United States, as “industrial-organisational (I-O) psychology.”
Infantile amnesia
The near-universal inability to recall memories from one's earliest years of childhood. Psychoanalytic theory explains this as a form of repression; other proposed explanations include the absence, at that age, of language sophisticated enough to encode experiences into lasting memory, and the general immaturity of the infant nervous system.
Infantile birth theories
The explanations young children offer, before being told otherwise, for the question “where do babies come from?” — the navel is apparently a particularly popular answer.
Infantilism
A condition in which a person has not psychologically matured beyond an infantile stage of development, or reverts to such a state later in life under stress or disturbance.
Inferential statistics
Statistical procedures that allow researchers to draw generalised conclusions about a larger population based on findings from a smaller, representative sample of that population.
Inferiority complex
A concept from Alfred Adler describing an unconscious condition in which a person feels persistently inadequate and resentful, often centred on some physical characteristic they regard as a defect. The complex can produce distorted behaviour, most notably overcompensation — an exaggerated effort to counteract the perceived defect, sometimes invoked to explain unusually aggressive behaviour in physically small men.
Information processing
A central concept in cognitive psychology describing everything that happens mentally between a stimulus and a response, including perception, memory, thinking, problem-solving and decision-making. “Information,” in this sense, refers broadly to any mental content — an image, idea, fact or opinion.
Information technology
The microelectronic means of transmitting, storing, processing and using information, whether in the form of words, numbers or images.
Information theory
The mathematical study of the nature of information and how it is communicated, originating with mathematicians and engineers (notably Claude Shannon) but subsequently drawn on by psychologists and linguists studying communication and cognition.
Inhibition
The blocking of one physiological or psychological process by another — for instance, activity in one sense receptor suppressing response to another, or fear preventing an escape response. In psychoanalysis, inhibition specifically describes an id impulse being blocked from reaching consciousness by the superego, which is distinct from repression, where the impulse is actively and more forcefully held back.
Inkblot test
See Rorschach test — the well-known projective test using ambiguous inkblot images.
Innate
Describing a genetically inherited tendency or characteristic present from birth, even if it does not become active or apparent until later in life. Compare with congenital, which describes a characteristic present at birth without necessarily being genetically inherited.
Innate releasing mechanism
A concept introduced by ethology pioneer Niko Tinbergen, based on his observations of stickleback fish. Male sticklebacks, who had never seen a female before reaching sexual maturity, still reliably knew to chase off rival males and court females — responding specifically to the presence or absence of red colouring on the belly of the fish they encountered. This specific triggering stimulus is what “releases” the fish's innate behavioural response.
Inner-directed
A term introduced to American sociology by David Riesman for people who respond to social pressures and change primarily on the basis of personal values internalised early in life. Contrast with outer-directed, describing people more responsive to the shifting expectations of their peers.
Inoculation
In social psychology, a technique for strengthening a person's existing attitude, and their resistance to future persuasion, by first exposing them to a small, manageable dose of an opposing argument.
Insight learning
The often sudden appearance of understanding while working through a problem, involving both the discovery of a cognitive solution to a practical difficulty (as in the aha reaction) and the kind of self-understanding sought in psychotherapy. Contrast with trial and error learning, which proceeds through repeated attempts rather than sudden comprehension.
Instinct
An innate, unlearned impulse or behaviour pattern, fixed and largely unchanging, shared by all members of a species; the study of instinctive behaviour in animals falls within ethology. Describing any specific human behaviour as “instinctive” tends to provoke considerable, often politically charged, controversy, and the concept is generally considered of limited value in explaining human behaviour, most of which is learned.
Institutional racism
Racially prejudiced outcomes that arise not from individuals' conscious intent, but simply from conforming to the established norms and conventions of a society whose institutions — law, government, education, business — systematically disadvantage particular racial groups.
Institutionalisation
Used both for the act of committing someone to an institution, such as a psychiatric hospital, and for the resulting state of a long-term resident who has adapted so completely to institutional life that they become unable to function independently outside it.
Instrumental aggression
A term from social psychology for aggression carried out not for its own sake, but as a means to achieve some other goal — illustrated by the psychological difference between killing an enemy face-to-face and remotely launching a missile from a great distance.
Instrumental conditioning
See operant conditioning — an alternative name emphasising that the organism's behaviour is “instrumental” in producing its consequences.
Integration
The process of organising separate parts into a coherent whole of a higher order — a concept applied across science, from the coordination of nerve impulses underlying any behaviour to the organisation of an entire society.
Intellectualising
Approaching a situation in purely intellectual, abstract terms while ignoring or denying the emotional content involved; regarded in psychoanalysis as a defence mechanism that protects the ego from uncomfortable feelings.
Intelligence
A concept psychologists have debated since the 1870s without reaching full agreement on its definition. Most would agree that heredity sets some limits on a person's intelligence, and that the capacity to learn — handling abstract ideas, adapting to new situations, perceiving complex relationships — is a marker of high intelligence, though this offers only a loose working definition. Intelligence is often cited as a clear example of a phenotype, the observable outcome of both genetic potential and environmental influence.
Intelligence quotient
A score derived from an intelligence test by dividing a person's mental age (as measured by the test) by their actual chronological age and multiplying by 100 (IQ = MA/CA × 100). An IQ score on its own has no absolute meaning — it does not measure intelligence the way a tape measure measures height — but only reflects a comparison against everyone else who has taken that particular test, with the average score conventionally set at 100.
Intelligence test
A test intended to measure intelligence, used to distinguish higher- and lower-scoring individuals for educational, occupational or social purposes. In the absence of a fully agreed definition of intelligence itself, the practical, or operational, definition risks circularity — people are said to score well because they are intelligent, and to be intelligent because they score well. There is also considerable evidence that intelligence tests have historically been biased in favour of white, urban, middle-class test-takers in the design and selection of their items.
Interaction process analysis
A technique for systematically recording and analysing the patterns of interaction between people within a face-to-face group.
Interaction recorder
A device used to time and record different categories of interaction occurring within face-to-face groups, for research purposes.
Intercorrelations
A table displaying the correlations calculated between every possible pair within a set of variables, used especially in factor analysis.
Interference
A term with two main psychological meanings: (1) the change in perception that occurs when two light or sound waves, out of phase with one another, combine; and, more commonly, (2) the process by which one instance of learning disrupts or inhibits another, as studied in memory research.
Intermittent reinforcement
In a conditioning experiment, rewarding an animal for correct responses only some of the time, rather than every time. This tends to produce conditioning that is slower to establish but considerably more resistant to extinction than continuous reinforcement.
Internal justification
In social psychology, a way of resolving cognitive dissonance that underlies particularly durable attitude change: rather than justifying an uncomfortable choice with an external reason (“I only do it for the money”), a person instead comes to genuinely see the situation more positively — for example, focusing on an unappealing job's more rewarding aspects — thereby changing the underlying attitude itself.
Internalisation
The process of accepting external ideas, values or standards as one's own, to the point where their original outside source is no longer consciously recognised. Its best-known example is the superego, in which the values of parents and wider society become built into the developing personality.
Interpersonal attraction
A general term for the area of social psychology concerned with understanding why people are drawn to one another. See also: gain-loss theory of interpersonal attraction.
Interposition
A depth cue in which one object partially blocks another from view, providing information that the blocking object is nearer to the observer.
Intervening variable
A hypothetical process or variable assumed to occur between a stimulus and a response, inferred rather than directly observed. See also: black box.
Intrapsychic
Describing conflicts or processes occurring entirely within the psyche — that is, within the mind, personality or self — as distinct from conflicts between a person and their external environment.
Intrinsic motivation
Doing something for its own sake, because the activity itself is rewarding, rather than for any external reward or consequence. Always contrasted with extrinsic motivation. See also: functional autonomy.
Intropunitive
Characteristically responding to frustration by blaming, punishing or feeling guilt and humiliation toward oneself. Contrast with extrapunitive, in which frustration is directed outward at others.
Introspection
The deliberate process of examining and reporting on the contents of one's own mind — one of psychology's earliest research methods, associated particularly with Wilhelm Wundt's early laboratory studies.
Introversion
In Carl Jung's theory, a fundamental personality dimension characterised by a withdrawn, inward-looking and relatively passive orientation. Usually contrasted with extraversion.
Involution
Literally the opposite of evolution — decline or deterioration, used particularly to describe the physical and psychological changes and crises associated with midlife. See also: involutional melancholia, middlescence.
Involutional melancholia
A state of depression and anxiety traditionally associated with menopause and with midlife crises more generally; the term is now largely superseded in clinical use by more specific modern depressive diagnoses.
IQ
An abbreviation for intelligence quotient — see that entry.
IRM
An abbreviation for innate releasing mechanism — see that entry.
Irrational
Describing thought or behaviour that is inconsistent with logic or reason.
Ishihara test
A widely used test for colour blindness in which a person is asked to identify a number or pattern embedded within a background of dots in different, carefully chosen colours; people with normal colour vision can perceive the pattern clearly, while people with colour blindness generally cannot.
Isomorphic
An idea, revived by Gestalt psychology, proposing a direct, one-to-one correspondence between a perceived stimulus and its representation in the brain. The concept has now largely been abandoned in mainstream neuroscience and cognitive psychology.
IT
An abbreviation for information technology — see that entry.
Item analysis
A statistical technique used to evaluate how effectively individual items on a test discriminate between higher- and lower-scoring test-takers, informing the refinement of psychometric instruments.
