Glossary of Psychological Terms
Definitions of terms used in psychology, psychometric testing and occupational assessment, organised alphabetically.
Labelling theory
In social psychology, an account of deviant behaviour that focuses on how other people react to, and label, the person seen as deviant, rather than on the behaviour itself. Combined with the self-fulfilling prophecy, labelling theory has also been used to explain the persistence of psychotic behaviour: once a person is labelled, say, paranoid, everything they subsequently do tends to be interpreted through that lens, reinforcing the original label.
Labile
Describing emotional expression that shifts freely, rapidly and often unpredictably from one state to another.
Laing, Ronald D. (1927-1989)
A Scottish psychiatrist whose sweeping criticisms of conventional psychiatric diagnosis and treatment proved highly influential. A leading figure in the existential psychiatry movement, Laing focused particularly on the roots of emotional disturbance within disturbed patterns of family relationships.
Language codes
See elaborated code and restricted code, Basil Bernstein's two contrasting styles of communication.
Latent content
In psychoanalysis, the hidden, repressed underlying meaning of a dream, as distinct from its manifest content — the dream as consciously remembered and reported.
Latent learning
See incidental learning — learning that occurs without deliberate, conscious effort and may not become apparent until relevant later.
Lateral thinking
A term coined by Edward de Bono for an approach to problem-solving that deliberately looks at a problem from multiple, unconventional angles rather than tackling it head-on, allowing it to be reframed in ways that reveal previously unconsidered solutions. A form of heuristic.
Lateralisation
The process, assumed to occur in brain development, by which each of the two cerebral hemispheres comes to specialise in particular psychological functions, such as language typically lateralising to the left hemisphere.
Laterality
Literally “sidedness”: a person's preference for using one hand, foot or eye over the other for tasks that could be performed with either. See also: bilateral transfer.
Law of parsimony
See Occam's razor — the principle that the simplest adequate explanation for a phenomenon should be preferred over a more complex one.
Laws of association
The principles thought to underlie the connections formed in memory between particular ideas, feelings or behaviours — first systematically formulated by Aristotle in the fourth century BC, and foundational to later associationist theories of learning.
Lay analyst
The term for a psychoanalyst who practises without holding a medical degree, having trained instead through psychoanalytic institutes.
Learned helplessness
The finding that animals or people who have previously experienced a situation in which they could not avoid punishment or an aversive outcome go on to behave passively and give up trying, even later, in situations where they genuinely do have the power to avoid it — an influential concept in understanding depression.
Learning curve
A graph plotting measured changes in learning performance against time or practice, typically showing rapid initial gains that gradually level off.
Learning plateau
A period during which a learning curve flattens out, reflecting a temporary halt in visible progress despite continued practice.
Learning set
Sometimes described as “learning how to learn”: a generalised strategy or approach that a person or animal carries over from one learning situation into a new one, drawing on previously successful responses and strategies. Underlies the broader phenomenon of transfer of training.
Learning styles
The different approaches individuals characteristically take to learning, attributed to individual differences in cognition and personality; though popular, the scientific evidence that matching instruction to a person's preferred “learning style” improves outcomes is weak.
Learning theory
Any of the various systematic attempts within psychology to explain the process and mechanisms of learning, spanning behaviourist, cognitive and social-learning approaches.
Lesion
Damage to bodily tissue caused by injury, disease or surgery; in the study of behaviour, the term is most often used specifically for brain damage, including deliberately induced lesions used in animal research to study brain function.
Level of aspiration
The particular goals or standards of performance a person sets for themselves in a given task or area of life, which may be realistic or unrealistic relative to their actual ability.
Levels of processing
The theory that how deeply information is processed during learning determines how well it is retained in long-term memory: the more meaning a person extracts from and connects to a stimulus, the deeper the processing, and the more likely the information is to be remembered.
Levels of significance
See statistical significance — the threshold probability used to decide whether an observed research result is unlikely to have occurred by chance alone.
Lewin, Kurt (1890-1947)
A psychologist trained under the early Gestalt theorists who applied their principles to social psychology, where he pioneered the study of group dynamics and developed influential concepts including life space and the classic conflict types (approach-approach, approach-avoidance, avoidance-avoidance).
Lie detector
An instrument, more formally called a polygraph, that monitors physiological changes such as heart rate and the skin's electrical resistance under conditions of emotional stress, on the assumption that a person will show detectable signs of emotional arousal if they lie in response to a question — an assumption considered scientifically shaky, with the technique widely regarded as unreliable for reliably detecting deception.
Life instinct
In Freud's theory, an unconscious drive, or set of drives, oriented toward preserving and enhancing life, drawing its energy from the libido. Always contrasted with the death instinct.
Life space
A term introduced by Kurt Lewin for the total combination of physical and psychological factors making up an individual's or group's environment at a given moment, and which together determine their behaviour.
Limbic system
A network of interconnected brain structures thought to play a central role in regulating emotion and motivation, forming part of what is sometimes informally called the “old brain” for its evolutionarily ancient origins.
Limen
See threshold — the minimum level of stimulus intensity needed to produce a detectable sensation or response.
Linguistic determinism
The hypothesis, associated with Benjamin Lee Whorf, that the range of thoughts available to a person is shaped, and potentially limited, by the structure and vocabulary of the language they speak.
Linguistic relativity
See linguistic determinism — sometimes used as a softer version of the same underlying hypothesis, suggesting language influences rather than strictly determines thought.
Little Albert
The infant conditioned by behaviourist John B. Watson, in a famous and now ethically controversial 1920 experiment, to develop a fear response to a white rat by pairing it with a loud, frightening noise.
Little Hans
A young patient of Sigmund Freud's, treated (via the boy's father) for a phobia of horses, and the subject of one of Freud's most detailed published case studies. Not to be confused with Clever Hans, the arithmetic-performing horse.
Lloyd Morgan's Canon
A principle proposed by British comparative psychologist C. Lloyd Morgan in 1894, holding that any interpretation of an animal's behaviour should invoke the simplest possible psychological process capable of explaining it — a higher-level explanation should not be offered when a lower-level one will suffice. A specific application of Occam's razor to animal behaviour.
Lobotomy
A form of psychosurgery in which the connections between the brain's frontal lobes and the rest of the brain are severed. Once used, as a last resort, to treat severe depression and other serious mental illness, the procedure is now rarely performed given its serious and often irreversible side effects, and the availability of far less invasive treatments.
Localisation
In general use, identifying the source or location of a particular stimulus; in psychology, most often encountered specifically as brain localisation, the association of particular psychological functions with particular brain regions.
Locus of control
A personality dimension describing whether a person generally attributes the outcomes in their life to their own actions (an internal locus of control) or to external forces, luck, or other people (an external locus of control).
Long-term memory
The relatively permanent store of memory, capable of holding vast amounts of information over long periods, as distinct from the much more limited and temporary short-term memory and sensory memory.
Longitudinal research
A research design that studies the same group of people repeatedly over an extended period of time, allowing researchers to track change within individuals directly. Compare with cross-sectional research, and see also: cohort effect.
Lorenz, Konrad (1903-1989)
An Austrian pioneer of ethology whose popular books, including King Solomon's Ring and On Aggression, helped bring the scientific study of animal behaviour to a wide general readership; also known for his research on imprinting in young geese.
LTM
An abbreviation for long-term memory — see that entry.
