Intelligence — its meaning and nature, and the theories

What this heading covers

The theories, asked as straightforward "who said what" questions, and the idea the CTET heading calls multi-dimensional intelligence — the position, now the standard one, that intelligence is several things rather than one.

Nearly every mark here is recoverable if the names are firmly attached to the claims, which is why the names come with a one-line hook below.

Measuring intelligence, the critical perspective on the construct, and the educational implications are a heading of their own and have a lesson of their own.

What intelligence is said to be

There is no single agreed definition, and the papers exploit that by quoting one. The usual working definition is the ability to learn from experience, reason, solve problems and adapt to new situations.

Who	What they called it
Binet	The ability to judge well, understand well and reason well
Terman	The ability to carry on abstract thinking
Thorndike	The power of good responses from the point of view of truth or fact
Stern	The general capacity to adjust one's thinking to new requirements
Wechsler	The aggregate capacity to act purposefully, think rationally and deal effectively with the environment
Piaget	The ability to adapt — to assimilate and to accommodate

Terman's definition is the one most often quoted in a question, and Wechsler's is the one that reads most like a modern textbook because it treats intelligence as global rather than as a single faculty.

The nature of intelligence

• It is a capacity, not a store of knowledge — which is why an uneducated adult may be highly intelligent and a well-taught child may not be.
• It is the product of heredity and environment interacting, like everything else in this subject.
• It is distributed normally across a population: most people near the middle, few at either extreme.
• It grows with age and then levels off, with the sharpest growth in childhood.
• It differs between individuals and within one individual — a single person is stronger at some things than others, which is the observation the whole multi-dimensional argument rests on.

Four words that are constantly confused

Term	What it is about
Intelligence	General capacity to learn, reason and adapt — the whole
Aptitude	Potential in a specific field, used to predict how well someone could learn it
Achievement	What has actually been learnt already — the past, not the potential
Attitude	A disposition for or against something; a matter of feeling and tendency, not of capacity

The pairing a question sets most often is aptitude against achievement: aptitude looks forward and asks what this person could become good at, achievement looks back and asks what they have already learnt.

The argument every theory is answering

Is intelligence one thing or many? Spearman says essentially one. Everybody after him says more than one, and they differ about how many and of what kind. Hold the list in that order and the theories stop being a set of names to memorise.

Spearman — the two-factor theory

Charles Spearman (1904) noticed that people who did well on one mental test tended to do well on others. He explained the pattern with two factors:

• g, the general factor — a single underlying mental energy running through every intellectual activity, innate and common to all tasks.
• s, the specific factors — abilities particular to one task and shared with no other.

Performance on any task is g plus the relevant s. The more g a task demands, the more its results agree with other tasks.

The hook: Spearman is the one who said intelligence is essentially one thing. Everything after him is an argument with that sentence.

Thorndike — the multifactor theory

Edward Thorndike rejected g altogether. Intelligence, he argued, is a collection of many independent abilities with no general power behind them; if scores correlate at all it is because the tasks share specific elements, not because a single energy drives both.

He is remembered for three kinds, and the three are a favourite question:

Kind	What it works on
Abstract	Ideas, words, symbols — the kind school examines
Mechanical or concrete	Objects, tools, machines, the hands
Social	People: understanding them and acting well with them

The hook: Thorndike is the one who denied g. Spearman proposed it; Thorndike denied it. A paper that swaps those two names is relying on the commonest error in this heading.

Thurstone — primary mental abilities

Not a named heading, but it appears as an option often enough to be worth holding. L. L. Thurstone took the middle position: not one factor and not countless ones, but seven primary mental abilities — verbal comprehension, word fluency, number, space, memory, reasoning and perceptual speed.

The hook: Thurstone is the one with the number seven — and so is Gardner's original list, which is why the two get confused. Thurstone's seven are abilities; Gardner's are intelligences, and the claim behind the word is much stronger.

Guilford — the structure of intellect

J. P. Guilford built a three-dimensional model in which every intellectual act is classified on three axes at once.

Axis	Meaning	Its categories
Operations	What the mind does	Cognition, memory, divergent production, convergent production, evaluation
Contents	What it does it to	Figural, symbolic, semantic, behavioural
Products	The form of the result	Units, classes, relations, systems, transformations, implications

Five operations × four contents × six products = 120 distinct abilities in the original model, which Guilford later extended by subdividing the categories. The number 120 is the one the papers ask for.

Convergent and divergent thinking

The part of Guilford most useful to a teacher, and the part most often examined:

	Convergent thinking	Divergent thinking
Aim	The one correct answer	Many possible answers
Measured by	Accuracy	Fluency, flexibility, originality, elaboration
Typical question	"What is the capital of Bihar?"	"How many uses can you find for a brick?"
Underlies	Conventional examination success	Creativity

Guilford's charge is simple and testable in a question: a school that sets only one-right-answer questions never sees divergent thinking, and the children soon learn that offering a second possibility is a waste of effort.

The hook: Guilford is 120 and divergent thinking.

Gardner — the theory of multiple intelligences

Howard Gardner (Frames of Mind, 1983) argued that intelligence is not one capacity but several relatively independent ones, each with its own developmental course — and that schools recognise only the first two on his list.

Intelligence	Strong in	The kind of person
Linguistic	Words, reading, writing, argument	Writer, lawyer, teacher
Logical-mathematical	Number, reasoning, patterns	Mathematician, scientist
Spatial	Images, maps, design, visualising	Architect, surgeon, artist
Bodily-kinaesthetic	Movement, sport, craft, dance	Athlete, dancer, mechanic
Musical	Rhythm, pitch, melody	Musician, composer
Interpersonal	Understanding and working with other people	Leader, counsellor, salesperson
Intrapersonal	Understanding oneself	Anyone who knows their own mind well
Naturalistic	Recognising and classifying living things	Farmer, botanist, ecologist

The first seven are the original list; naturalistic was added later, and Gardner has discussed an existential candidate without ever settling it — so eight is the number to give, with the caution that a question may say "seven" if it means the original set.

Two things that are regularly asked:

• These are intelligences, not learning styles. A style is a supposed preference for how to receive information; Gardner is claiming different kinds of ability. Calling his list "learning styles" is wrong, and the styles idea is separately and heavily criticised.
• The educational claim is the point. A child weak in the first two is not unintelligent, and teaching that offers only words and numbers gives most children only two ways in.

The hook: Gardner is eight kinds of intelligence.

Sternberg — the triarchic theory

Robert Sternberg proposed that intelligence has three aspects working together — three parts of one thing, which is what separates him from Gardner's several things.

Aspect	Also called	What it does
Componential	Analytical	Analysing, comparing, evaluating, criticising — what school and conventional tests measure
Experiential	Creative	Dealing with novelty, inventing, combining ideas in new ways, making routine what was once hard
Contextual	Practical	Adapting to an environment, shaping it, or choosing a different one — everyday competence

Sternberg's charge against traditional testing is that it captures the analytical and misses the other two, which is why people who test unremarkably are sometimes strikingly effective in life. He later called the combination successful intelligence: the balance a person strikes between the three in pursuit of their own goals.

The hook: Sternberg is three aspects — analytical, creative, practical.

Two more the papers use

Neither is a named heading, and both turn up as options.

• Cattell divided g into fluid intelligence (Gf) — reasoning with the unfamiliar, largely independent of schooling, which peaks early and declines gently — and crystallised intelligence (Gc) — accumulated knowledge and skill, which keeps rising into later life. The pair explains how an older person can be slower at a puzzle and far better at a judgement.
• Vernon proposed a hierarchical model: g at the top, dividing into two major group factors — verbal-educational (v:ed) and practical-mechanical-spatial (k:m) — and these into minor group factors and then specific ones. It is the compromise between Spearman and Thurstone.

The whole list at a glance

Theorist	The claim	The number to remember
Spearman	One general factor plus task-specific ones	2 factors — g and s
Thorndike	Many independent abilities; no g	3 kinds — abstract, mechanical, social
Thurstone	A middle group of primary abilities	7 primary mental abilities
Guilford	Every act is operation × content × product	120 abilities
Gardner	Several independent intelligences	8 intelligences
Sternberg	Three aspects of one intelligence	3 — analytical, creative, practical
Cattell	g splits in two	Fluid and crystallised
Vernon	g at the top of a hierarchy	v:ed and k:m

Questions of the kind the paper sets

A child struggles with written work but plays in the school band, learns tunes after hearing them once and organises the group's rehearsals. According to Gardner, this child —

Two of Gardner's intelligences are on display: musical, and interpersonal in the organising. The trap is the option saying the child has low intelligence or is "weak but talented in music" — Gardner's whole claim is that these are intelligences, not compensations for lacking one. The expected answer names them as strengths in their own right, and the teaching implication is to offer routes into written work through the strengths the child already has.

The general factor g was proposed by — (a) Thorndike (b) Spearman (c) Gardner (d) Thurstone

Which theorist denied the existence of a general factor altogether? (a) Spearman (b) Vernon (c) Thorndike (d) Cattell

Guilford's structure-of-intellect model classifies every intellectual act by — (a) verbal, numerical and spatial ability (b) operations, contents and products (c) analytical, creative and practical aspects (d) fluid and crystallised intelligence

"How many different uses can you think of for a newspaper?" chiefly tests — (a) convergent thinking (b) divergent thinking (c) memory (d) perceptual speed

Gardner's naturalistic intelligence is the ability to — (a) survive out of doors (b) recognise and classify living things and features of the natural world (c) study science at a high level (d) remain calm under pressure

The ability to deal with an entirely novel problem belongs, for Sternberg, to the — (a) componential aspect (b) experiential aspect (c) contextual aspect (d) crystallised factor

A pupil who does poorly in written examinations but repairs the school's furniture skilfully is best described, in Thorndike's terms, as strong in — (a) abstract intelligence (b) mechanical intelligence (c) social intelligence (d) g

Which pair is correctly matched? (a) Gardner — triarchic theory (b) Sternberg — multiple intelligences (c) Thurstone — primary mental abilities (d) Guilford — two-factor theory

Accumulated knowledge and vocabulary, which keep increasing into later life, are what Cattell called — (a) fluid intelligence (b) crystallised intelligence (c) the general factor (d) perceptual speed

"Multi-dimensional intelligence", as the CTET syllabus uses the phrase, is best represented by — (a) Spearman's g (b) Gardner's account of several relatively independent intelligences (c) the ratio formula for IQ (d) Binet's scale

Mistakes that cost marks here

• Attaching g to the wrong person. Spearman proposed the general factor; Thorndike denied it.
• Confusing convergent and divergent thinking. Divergent generates many answers and underlies creativity.
• Muddling Gardner with Sternberg. Gardner lists eight kinds of intelligence; Sternberg gives three aspects of one.
• Confusing Thurstone's seven abilities with Gardner's original seven intelligences.
• Calling Gardner's list "learning styles". They are proposed intelligences, and the styles literature is a separate and much-criticised idea.
• Giving Guilford's model as two dimensions, or forgetting the number 120.
• Confusing aptitude with achievement — aptitude looks forward, achievement looks back.
• Treating intelligence as the same as knowledge, when it is the capacity to acquire and use it.

In one line

Spearman said intelligence is essentially one thing; Thorndike, Thurstone, Guilford, Gardner and Sternberg all said it is several — and the whole heading is best held as that one argument, with each name attached to its own number.

In the classroom

Give a class one task a week that has no single right answer — more than one way to sort the same set of objects, several possible endings for a story, as many uses as they can find for one ordinary thing. It takes ten minutes, it is the only part of Guilford that a timetable will actually let you teach, and it tells you things about children that no test on this page would ever have shown you.