Glossary of Psychological Terms
Definitions of terms used in psychology, psychometric testing and occupational assessment, organised alphabetically.
MA
An abbreviation for mental age — see that entry.
Machiavellianism
A personality characteristic marked by a willingness to manipulate and exploit others for personal gain, with little regard for conventional morality. Named after the political writings of the fifteenth-century Italian statesman Niccolò Machiavelli, and now also studied as one of the “Dark Triad” personality traits alongside narcissism and psychopathy.
Magic thinking
Any attempt to understand or influence events through recourse to supernatural forces, particularly the belief that one's own wishes can causally affect the real world — “wishing can make it so.” Considered typical of young children, some psychotic states, and pre-literate belief systems, though traces of it are easy to find in ordinary adult behaviour in modern societies as well.
Mandala
In Carl Jung's theory, a circular symbol representing the striving for wholeness and unity of the self, drawing on similar symbols of the cosmos found across many different cultures and religious traditions.
Mania
A state of uncontrollable excitement and elevated energy, often accompanied by a strong impulse toward a particular pattern of behaviour; the elevated phase of bipolar disorder, and also used as a suffix for specific compulsive urges (as in kleptomania).
Manic
Describing behaviour characteristic of mania — marked by excessive energy, elevated mood, and often impulsivity.
Manic-depressive
An older term for the psychotic mood disorder marked by extreme swings between the euphoric excitement of mania and the hopelessness and anxiety of severe depression; the ordinary ups and downs of mood in most people are far milder versions of the same underlying dimension. Now generally referred to clinically as bipolar disorder.
Manifest content
In psychoanalysis, the consciously remembered and reported surface content of a dream, as distinct from its latent content — the hidden, repressed meaning the manifest content is thought to disguise.
Mantra
A word or phrase repeated continuously as an aid to concentration and meditation.
Marasmus
Severe physiological wasting and weakness in infants, resulting from prolonged deprivation of adequate food, care or affection.
Marginality
In social science, the effects on an individual or group of being excluded from, or existing at the edges of, the social and economic mainstream of a society.
Masking
The blocking or obscuring of one sensory stimulus or process by the presence of another, more dominant one.
Maslow, Abraham (1908-1970)
An American personality theorist and leading figure in humanistic psychology, best known for his hierarchy of needs and his concepts of the peak experience and self-actualisation — the realisation of one's fullest personal potential.
Maternal deprivation
The lack of adequate care, affection and attentive handling normally provided by a mother or primary caregiver, particularly damaging during the first few years of life, considered the optimal period for forming secure social attachments. Children who experience severe maternal deprivation, such as those raised in institutional settings, frequently show later physical, psychological or social difficulties. See also: Bowlby, John.
Matriarchy
A society or social group in which women hold the primary positions of authority and leadership. Contrast with patriarchy.
Matrilineal
Describing a society or social group in which lineage, descent or inheritance is traced through the mother's side of the family. Contrast with patrilineal.
Maturation
In psychology, the processes of growth and development common to all members of a species, unfolding on a broadly similar schedule regardless of individual heredity or specific environment — a concept that cuts across, and complicates, the traditional nature-nurture debate.
Maze
An apparatus used to study learning in both animals and humans, ranging from a simple T-junction offering a choice between two paths to an elaborate, multi-branched labyrinth.
McNaughten rules
A mid-nineteenth-century English legal ruling, still influential in many jurisdictions' criminal law, used in determining whether a defendant can be considered legally insane and therefore not criminally responsible. Under the rule, a person is presumed criminally liable unless their reasoning was so impaired that they did not understand the nature of their act, or did not know it was wrong.
Mean
In statistics, the most commonly used measure of central tendency: the arithmetic average, calculated by summing a set of values and dividing by the number of values.
Measures of central tendency
The three main statistics used to describe the central, typical value of a set of numbers: the mean, the median, and the mode.
Median
In statistics, the measure of central tendency that divides an ordered set of scores exactly in half, with as many scores falling above it as below it.
Mediate
In psychology, describing a process, often cognitive, that occurs between a stimulus and the resulting response, helping to explain how the two are connected.
Medical model
The framework that treats psychological disturbance as fundamentally a medical condition, to be diagnosed and treated by physicians, typically with medication. Contrasted with alternative frameworks such as those proposed by the existential psychiatry movement.
Medulla (oblongata)
The lowest part of the brainstem, linking the brain to the spinal cord, which helps regulate essential automatic bodily functions such as blood pressure, heart rate and breathing.
Megalomaniac
A person with a grossly inflated, unrealistic sense of their own importance, abilities or power.
Melancholia
An older clinical term for a pathological degree of low, sorrowful mood, marked by profound sadness and severe depression. See also: involutional melancholia.
Membership group
In social psychology, the group to which a person actually, formally belongs. Compare with reference group, the group whose standards and values a person uses to evaluate themselves, which need not be the same group.
Memory
A term used in three related senses: (1) the cognitive function of encoding, retaining and retrieving information about past experience; (2) the underlying system or systems responsible for storing that information; and (3) the actual content of what is remembered.
Memory span
The number of discrete items a person can accurately recall immediately after a single presentation of the material. See also: digit-span test.
Memory trace
See engram — the hypothesised physical trace a memory leaves in brain tissue.
Mental age
A score derived from an intelligence test, in which test items are graded by difficulty and calibrated against the typical performance of children at each chronological age. See also: intelligence quotient.
Mental defective
An older, now considered outdated and offensive, general term for a person judged to have insufficient mental development to manage ordinary daily life without additional support.
Mental retardation
An older technical term, once standard in Britain and North America, for significant intellectual disability, generally defined as an IQ score below 70; now widely replaced in professional use by “intellectual disability.”
Mental set
A person's expectation of, or readiness for, a particular kind of experience or problem, which can shape (and sometimes bias) how they perceive and respond to a new situation.
Mere exposure
A term introduced by psychologist Robert Zajonc for the finding that, all else being equal, simple repeated exposure to an unfamiliar object, word or image tends to increase how much people like it. Often cited as a partial explanation for the effectiveness of repetitive advertising in shaping consumer preference.
Merrill-Palmer scale
A test of verbal and manual manipulative ability designed for use with young children.
Mesmerism
An early name for hypnosis, derived from the eighteenth-century Austrian physician Franz Mesmer, who developed and popularised the technique under the name “animal magnetism.”
Meta-analysis
A statistical technique for combining and jointly analysing the results of multiple separate studies on the same question, in order to identify overall patterns and trends with greater statistical power than any single study alone.
Metacognition
In cognitive psychology, awareness and understanding of one's own cognitive processes — in effect, thinking about one's own thinking, including monitoring how well one understands or remembers something.
Metapsychology
A term used in two distinct senses: either (1) an ambitious attempt to unify the whole of psychology within a single comprehensive theoretical framework, or (2) speculation that goes beyond existing theory and evidence to address broader questions about the human condition.
Middlescence
A term used within developmental psychology to draw attention to the particular psychological stresses and conflicts of the middle years of adult life, as well as its distinctive and potentially positive aspects.
Milieu therapy
A form of psychotherapy that seeks to help a person by deliberately changing aspects of their surrounding environment, rather than working directly on their individual attitudes or behaviour.
Miller Analogies Test
A test using difficult verbal analogy problems, developed to help predict future academic performance among applicants to graduate programs at American universities.
Mind
A term used loosely for centuries in many different senses; as generally used by psychologists today, it refers to the whole organised system of, primarily cognitive, mental processes — perception, thought, memory and reasoning.
Mind map
A visual note-taking and thinking technique, developed in the 1970s by Tony Buzan, that radiates outward from a central theme using branching lines, shape and colour, intended to support memory, creative thinking and idea generation.
Mind-body problem
One of philosophy's oldest and most persistent questions: how are the mind and the physical body related? Proposed answers have included that mind and body fully interact and influence one another; that they do not interact at all but merely run in parallel; that mind does not really exist as anything distinct from physical brain processes; and that mind and body are, at bottom, one and the same thing.
Minimax strategy
In game theory, a decision strategy that seeks to minimise the maximum possible loss, rather than trying to maximise potential gain — a cautious, risk-averse approach to choosing among alternatives.
Minnesota Multiphasic Personality Inventory
A widely used paper-and-pencil personality test comprising 550 statements that a respondent rates as true or false of themselves. The overall pattern of responses is used to identify personality characteristics, particularly those associated with psychological disturbance, commonly known by its initials, the MMPI.
Mirror writing
Writing produced in reversed form, appearing normal only when viewed in a mirror. Occasionally observed in people diagnosed with schizophrenia, but more commonly seen in young children who have not yet firmly established their hand and directional laterality.
Misanthropic
Describing a disposition of hatred, distrust or contempt for other people in general.
Miscegenation
Technically, interbreeding between genetically distinct population groups; historically used, especially in the context of racial segregation, as a pejorative and scientifically unsound term for relationships or childbearing between people of different racial backgrounds, whose differences are substantially social and cultural rather than biological.
Misogyny
Hatred, contempt or deeply ingrained prejudice against women.
MMPI
An abbreviation for the Minnesota Multiphasic Personality Inventory — see that entry.
Mnemonics
Techniques and tricks used to aid memory, such as acronyms, rhymes, or vivid mental imagery, that make information easier to encode and later retrieve.
Modal personality
An anthropological term for a hypothetical individual whose personality represents the mode — the most statistically common pattern — within a particular group or society, used as a way of characterising that group's typical psychological profile.
Modality
In psychology, a term generally referring to a particular form or channel of sensory experience, such as vision, hearing or touch.
Mode
In statistics, a measure of central tendency referring to the value that occurs most frequently within a set of numbers.
Model
Either (1) a simplified way of representing patterns of relationship observed in human behaviour or mental processes, for research or theoretical purposes; or (2), in social psychology specifically, a person whose behaviour is observed and potentially imitated by others. See also: modelling.
Modelling
In social psychology, a form of learning through observing a model that goes well beyond simple copying or imitation. Children in particular may generalise from a model's specific behaviour to a much wider range of related behaviours of their own devising, rather than reproducing only what they directly observed.
Molar
Describing an activity or behaviour considered as a whole — swimming, for example — rather than broken down into its individual constituent movements. Contrast with molecular.
Molecular
Describing the individual constituent parts of a behaviour — the specific head, arm and leg movements that together make up swimming — rather than the activity considered as a unified whole. Contrast with molar.
Mongolism
See Down's syndrome. This older term, based on a now-discredited and offensive comparison of facial features, is no longer used.
Monogamy
A marriage system involving one husband and one wife for an indefinite period; the prevailing norm in most societies, though far from universal across all cultures and historical periods.
Monozygotic twins
Identical twins, developing from a single fertilised egg (zygote) that splits into two genetically identical embryos. Contrast with dizygotic twins.
Moral development
The area of developmental psychology studying how the capacity for moral judgement and reasoning changes over the lifespan; there is broad, though not universal, agreement that moral reasoning develops through a sequence of stages, as in Lawrence Kohlberg's influential theory, in a manner paralleling other aspects of cognitive development.
Moro reflex
The startle reflex seen in newborn infants, involving a sudden extension and then clutching motion of the arms and legs in response to a sudden loss of support or loud noise, first described by Austrian paediatrician Ernst Moro.
Motion parallax
A depth-perception cue based on relative movement: as an observer moves, nearby objects appear to move faster across the visual field than more distant objects.
Motivation
A general term covering the psychological processes involved in experiencing needs and drives, and the resulting behaviour directed toward goals that satisfy them.
Motor
In psychology, relating to muscular movement and the physical action of the body, as in “motor skills” or “motor cortex.”
Müller-Lyer illusion
A well-known visual illusion in which the perceived length of a line is distorted by the direction of arrow-like fins added to its ends; named after German sociologist and psychologist Franz Müller-Lyer, who first described it.
Multimodal distribution
A frequency distribution containing several distinct modes (peaks), suggesting the data may reflect more than one underlying group or process.
Multiple personality
A rare and dramatic form of dissociative disorder in which repression leads to the apparent splitting off of two or more seemingly complete, distinct personalities within the same individual, as in the fictional cases of Dr Jekyll and Mr Hyde or The Three Faces of Eve. This is what is popularly meant by “split personality,” now more formally termed dissociative identity disorder — not to be confused with the split-brain phenomenon, and never to be confused, as it commonly is in popular usage, with schizophrenia, an entirely distinct condition.
Mundane realism
A term used in social psychology for the degree to which an experimental situation resembles everyday, real-world experience, as distinct from experimental realism, which concerns whether the experiment captures the essential psychological forces of a real situation without needing to replicate its surface details.
Murphy's Law
The informal axiom holding that anything that can go wrong, eventually will — often described as an American or Irish variant of the broader folk principle known as Sod's Law.
