Glossary

A

accommodation

In Piaget's theory, changing a scheme — or building a new one — when an experience does not fit: the toddler notices that a cow is much bigger and does not bark, and forms a new concept. Together with assimilation it makes up adaptation. Read the article

activity theory

An approach developed by Alexei Leontiev from Vygotsky's ideas: the mind and abilities take shape through purposeful activity — with its motives, goals and tools — and through mastering what culture has built up, such as language. Children develop abilities by doing, not just by listening. Read the article

adoption studies

Research comparing adopted children with their birth parents, who gave them their genes, and with their adoptive parents, who give them their environment. Such studies show both influences: resemblance to birth parents, and higher scores for children raised in caring, stimulating homes. Read the article

aptitude

The potential to develop a particular ability quickly with the right teaching and practice, such as an aptitude for languages or for mechanics. Whether it grows into real skill depends on opportunity, effort and interest. Read the article

assimilation

In Piaget's theory, fitting a new experience into a scheme the child already has: a toddler who knows the word “dog” may call every four-legged animal a dog. It always works together with accommodation. Read the article

attention

The ability to pick out what matters, focus on it and ignore distractions. It is limited — the gate through which information reaches working memory — and depends on age, rest and interest, so short tasks, breaks and a calm setting help. Read the article

B

brain training

Commercial computer games and apps that promise to raise intelligence or memory through repeated drills. A major review found that people get better at the practised tasks, but the gains carry over little to other skills, school results or everyday life. Read the article

C

chunking

Grouping separate items into larger meaningful units so that working memory can hold more — a nine-digit phone number remembered as three groups. The more you know about a subject, the bigger the chunks you can form. Read the article

concrete operations

Piaget's stage from about 7 to 11–12 years, when children reason logically about real, tangible things — sorting, ordering, understanding conservation — but still struggle with purely abstract or hypothetical questions. Objects, drawings and examples help learning most at this stage. Read the article

conservation

Understanding that an amount stays the same when only its shape or arrangement changes — water poured into a narrower glass, or a clay ball rolled into a sausage. Children usually grasp it from about seven or eight: first for quantity, later for weight and volume. Read the article

convergent thinking

Thinking that narrows down to the single correct answer to a clearly set question, as in an arithmetic problem or a multiple-choice item. Guilford contrasted it with divergent thinking; most school and intelligence tests call mainly for this kind. Read the article

creativity

The ability to come up with ideas or products that are both new — at least to the person — and useful or fitting. It is not a rare gift of a few: everyone has some, and it grows with knowledge, practice, motivation and a supportive setting. Read the article

crystallised intelligence

The knowledge and skills built up through schooling, reading and experience — vocabulary, general knowledge, know-how in one's field. Cattell contrasted it with fluid intelligence; it can keep growing well into adulthood. Read the article

D

deviation IQ

The modern way of scoring IQ, introduced by David Wechsler (1939): a result is compared with others of the same age and expressed on a scale where the average is 100 and the standard deviation 15. Unlike the old mental-age ratio, it works for adults too. Read the article

divergent thinking

Thinking that branches out to produce many possible answers to an open question, such as “How many uses can you find for a brick?” Guilford linked it closely with creativity; it is often scored for fluency, flexibility and originality. Read the article

E

egocentrism

In Piaget's sense, a young child's difficulty in seeing things from another person's point of view — not selfishness. A preschooler may insist that her sister has no sister; play and discussion with other children gradually help to overcome it. Read the article

equilibration

In Piaget's theory, the child's own drive to restore balance: when ideas clash with each other or with reality, a moderate “imbalance” pushes the child to reorganise their thinking at a higher level. Piaget saw it as the main engine of development. Read the article

executive functions

The mind's “management” skills — holding information in mind, holding back impulses and switching flexibly between tasks — that let us plan, stay on track and adjust. They mature slowly through childhood and the teenage years, and games with rules and steady routines give them practice. Read the article

F

factor analysis

A statistical method that finds which test scores tend to go together across many people and so points to a few underlying abilities, called “factors”. It is a tool rather than a theory: Spearman, Thurstone and Carroll used it and arrived at different models. Read the article

fluency, flexibility and originality

Three ways of scoring divergent thinking: fluency is how many ideas a person produces, flexibility is how many different kinds of ideas, and originality is how unusual they are compared with others' answers. All three can be practised. Read the article

fluid intelligence

The ability to reason and solve new problems that depend little on what one has already learned — for example, spotting the rule in a series of unfamiliar shapes. Described by Raymond Cattell, it tends to be strongest in early adulthood. Read the article

Flynn effect

The rise in average IQ test scores — about 3 points per decade during the 20th century in many countries — documented by James Flynn (1984). It was too fast to be genetic, which shows how much schooling, nutrition, health and a more complex life matter. Read the article

formal operations

Piaget's final stage, from about 11–12 years: reasoning about abstract ideas and “what if” possibilities, forming hypotheses and testing them systematically. Modern research shows it develops unevenly — many adults use it mainly in fields they know well. Read the article

G

Gardner's criteria of an intelligence

The eight conditions Gardner checked before calling an ability an intelligence: brain damage can impair it on its own; it has prodigies, core operations, a path from novice to expert and evolutionary roots; experiments and tests support it; it has its own symbol system. Read the article

general factor g

A single general ability that, according to Charles Spearman (1904), explains why people who do well on one kind of mental test tend to do well on others. Today g heads most models of abilities, but it never captures all of a person's strengths. Read the article

H

heritability

An estimate of how much of the variation in a trait within a given population is linked to genetic differences. It describes groups, not individuals; for intelligence it is substantial and grows with age, but “heritable” does not mean “fixed”. Read the article

hierarchical (CHC) model of abilities

Today's mainstream picture of abilities, named after Cattell, Horn and Carroll: a general factor at the top, broad abilities such as reasoning, knowledge, memory and processing speed in the middle, and narrow skills at the base. It reconciles the “one ability” and “many abilities” views. Read the article

I

incubation (stages of creative thinking)

The second of Graham Wallas's four stages of creative thinking (1926): preparation, incubation, illumination and verification. After hard work on a problem you set it aside, and the solution may later arrive “out of nowhere” — so a break after real effort can help. Read the article

individual differences

The ways people differ from one another in abilities, interests, temperament and other traits, studied by differential psychology. On most traits people differ by degree rather than in kind, so labels like “able” and “not able” are unscientific. Read the article

inner speech

The silent talk in our heads that we use to plan and steer our actions. Vygotsky argued that it grows out of young children's out-loud self-talk at play, so a child talking to themselves while working is usually thinking, not misbehaving. Read the article

intellectual disability

Significant limitations, beginning in childhood, both in reasoning and learning and in everyday practical and social skills. It is diagnosed only after a full assessment by specialists, never from one test score, and early, patient support makes a real difference. Read the article

intelligence

The ability to understand ideas, learn from experience, reason, solve problems and adapt to new situations. Scientists still debate whether it is one general ability or a family of abilities; it is shaped by both heredity and environment. Read the article

intelligence quotient (IQ)

A score comparing a person's test performance with that of people the same age: it began as mental age divided by actual age (×100), and today 100 simply marks the average. It describes performance on certain tasks, not a person's worth or a fixed limit. Read the article

interest types (Holland)

John Holland's six broad types of work interests (RIASEC): realistic (hands-on), investigative (ideas), artistic (creating), social (helping), enterprising (persuading and leading) and conventional (order and data). Most people combine two or three, and interests work best as a guide alongside abilities. Read the article

K

kairos (the right moment)

The Greek word for the opportune moment — the brief window in which an action works best. Mētis means foreseeing it, waiting for it and seizing it, as a doctor must in treating an illness, or a parent in choosing when to raise a difficult subject. Read the article

L

learning styles

The popular idea that each person learns best through one channel — seeing, hearing or movement — and should be taught that way. People do have preferences, but research reviews have found no evidence that matching teaching to them improves learning. Read the article

long-term memory

The lasting store of our knowledge, skills and memories, with no known limit to its size. What counts is how well knowledge is organised and how easily it can be recalled — the main way experts differ from beginners. Read the article

M

mental age

A child's level on a test expressed as an age: an 8-year-old who solves the tasks that most 10-year-olds solve has a mental age of 10. It comes from the early age-graded tests, does not suit adults and is rarely used today. Read the article

mental test

A short task, given and scored in the same way for everyone, that measures a mental ability such as memory, attention or reasoning. James McKeen Cattell coined the term in 1890; his early tests of the senses and reaction speed predicted school success poorly. Read the article

metacognition

Thinking about your own thinking: knowing how you learn, planning a task, checking whether you have understood and changing strategy when something is not working. It can be taught — for example, by asking a child, “How will you check your answer?” Read the article

Mozart effect

The belief that simply listening to Mozart makes people — even babies — cleverer. Later analyses found the original effect small and short-lived; music is well worth enjoying and learning for its own sake. Read the article

multiple intelligences

Howard Gardner's theory (1983) of several relatively independent intelligences — now eight: linguistic, logical-mathematical, spatial, bodily-kinaesthetic, musical, interpersonal, intrapersonal and naturalist. It is a useful framework for noticing strengths and varying teaching, though its scientific basis is debated; it is neither a test nor a label. Read the article

mētis

The ancient Greek idea of shrewd, practical intelligence: foresight, flexibility, quick judgement and resourcefulness in changing situations, as shown by a helmsman, a craftsman or a doctor. Detienne and Vernant (1974) showed how central it was to Greek culture, though philosophers later pushed it aside. Read the article

N

neuromyth

A popular but mistaken belief about the brain, often used to sell products or justify teaching methods — for example, that we use only 10% of our brain, or that people are “left-brained” or “right-brained”. Read the article

normal distribution

The bell-shaped curve that describes how many traits, including test scores, spread across a large group: most people cluster near the average and fewer lie towards either end. On IQ tests about 68% of people score 85–115 and about 95% score 70–130. Read the article

norms (standardisation)

Reference results from a large, representative sample of each age group, against which one person's score is compared; standardisation also means giving and scoring the test the same way every time. Outdated norms, or norms from another country, can mislead. Read the article

O

object permanence

Understanding that objects go on existing when they are out of sight: the baby starts looking under the blanket for a hidden toy. Piaget traced its growth through the first two years; later studies suggest infants grasp some of it earlier than he thought. Read the article

P

practical intelligence

Skill with real-life problems — adapting to one's surroundings, shaping them or choosing better ones — a key part of Robert Sternberg's triarchic theory (1985). It can differ from school performance: Brazilian child street vendors calculated well at their stalls but worse on school-style problems. Read the article

primary mental abilities

About seven relatively distinct abilities identified by Louis Thurstone (1938): verbal comprehension, word fluency, number, space, memory, perceptual speed and reasoning. He preferred a profile to a single score; later the abilities were found to correlate, pointing to a general factor above them. Read the article

profile of intelligences

The particular pattern of stronger and weaker areas across the intelligences that every person has. It changes with experience and learning, so a profile is a starting point for conversation and planning, not a diagnosis or a label. Read the article

R

reliability

How consistent a test is: whether the same person would get a similar score on another day or with another version. Good intelligence tests are highly reliable, yet every score carries some error, so it is best read as a range. Read the article

retrieval practice

Learning by pulling information out of memory — quizzing yourself, using flashcards, retelling without the book — rather than simply rereading. Together with spacing study over several days, it is among the best-supported ways to learn. Read the article

reversibility

The ability to undo an action in one's head and return to the start: seeing that the water could be poured back, or that if 5 + 3 = 8, then 8 − 3 = 5. Piaget saw it as the hallmark of logical thinking. Read the article

S

scaffolding

Temporary help that an adult tailors to the learner — hints, breaking a task into steps, modelling, guiding questions — and gradually withdraws as the child gains skill, like scaffolding taken down from a finished building. The term comes from Wood, Bruner and Ross (1976). Read the article

scheme

In Piaget's theory, an organised pattern of action or thought that a child repeats and applies to new things — grasping, shaking, later sorting or counting. Schemes become richer and more connected through assimilation and accommodation. Read the article

spatial ability

The ability to picture objects in the mind, turn them around mentally and see how parts fit together — used in map reading, geometry, engineering, architecture, design and surgery. Construction toys, drawing, puzzles and maps give it plenty of practice. Read the article

special abilities

Abilities for particular kinds of work — verbal, numerical, spatial, mechanical, musical and others — that go beyond general intelligence. In hierarchical models they sit between g and narrow skills, and they are worth considering when choosing a field of study or a career. Read the article

standard deviation

A number showing how widely scores spread around the average; in a normal distribution about two-thirds of people fall within one standard deviation of it. On modern IQ tests it is 15 points, so a score of 115 is one standard deviation above average. Read the article

symbolic play

Pretend play in which one thing stands for another: a stick becomes a horse and a doll is put to bed. Appearing in the second year, it shows the new ability to think in symbols and helps the child make sense of experience. Read the article

T

tacit knowledge

Practical know-how picked up through experience rather than direct teaching, and often hard to put into words — for example, an experienced teacher's knack for calming a restless class. Sternberg saw it as the heart of practical intelligence. Read the article

twin studies

Research that compares identical twins, who share virtually all their genes, with fraternal twins, who share about half, to separate the roles of heredity and environment. Identical twins are more alike in measured intelligence, yet they still differ — a sign that environment counts too. Read the article

U

uneven profile (intra-individual differences)

Differences within one person: almost everyone is stronger in some abilities than in others, and the pattern shifts with age. A child who finds reading hard may shine at building or drawing, which is why a single overall score hides so much. Read the article

V

validity

Whether a test really measures what it claims to, and whether its scores predict what they should, such as later school results. A test can give very consistent scores and still measure the wrong thing. Read the article

W

working memory

The mind's “workbench”, which holds and uses a few pieces of information at once — keeping numbers in mind during mental arithmetic, or remembering a three-step instruction. Even in adults it holds only about four meaningful chunks, so long instructions easily overload it. Read the article

Z

zone of proximal development

Lev Vygotsky's term for the gap between what a child can do alone and what they can do with help from an adult or a more able peer. Teaching is most useful when tasks fall inside this zone — a step beyond independent work. Read the article