Intelligence defined: views of the lay public

High degree of similarity between the experts’ and laypeople’s conceptions of intelligence

Intelligence defined: views of scholars and test professionals

Francis Galton

  • First person to publish on heritability of intelligence
  • framed nature-nurture debate
  • Believed that the most intelligent persons were those equipped with the best sensory abilities
  • Following this logic, tests of visual acuity or hearing ability are tests of intelligence Alfred Binet
  • Wrote about components of intelligence
  • Reasoning, judgment, memory, abstraction
  • Called for more complex measurements of intellectual ability
  • Galton had viewed intelligence as a number of distinct processes or abilities that could be assessed only by separate tests
  • In contrast, Binet argued that when one solves a particular problem, the abilities used cannot be separated because they interact with one another to produce the solution

David Wechsler

  • Intelligence as an “aggregate” or “global” capacity
  • Non-intellective factors must be taken into account when assessing intelligence
  • Best way to measure this global ability was by measuring aspects of several “qualitatively differentiable” abilities —

(1) verbal based (2) performance based

  • Wechsler Adult Intelligence Scale (WAIS-III)
    • Verbal comprehension
    • Working memory
    • Perceptual organisation
    • Processing speed

Jean Piaget

  • Focused on the development of cognition in children
  • For Piaget, intelligence may be conceived of as a kind of evolving biological adaption to the outside world

As cognitive skills are gain, adaption (at a symbolic level) increases and mental trail and error replaces physical trial and error.

  • Process of cognitive development occurs neither solely through maturation or learning
  • Believed that as a consequence of interaction with the environment, psychological structures become reorganised
  • According to his theory, biological aspects of mental development are governed by inherent maturational mechanisms
  • As individual stages are reached and passed through, the child also experiences the environment
  • Each new experience required some form of cognitive organisation or reorganisation in a schema
  • Assimilation —> actively organising new info to fit what is already perceived and thought
  • Accommodation —> changing what is already perceived or thought so that it fits with new info

Factor-Analytic Theories of Intelligence

  • Theorists have used factor analysis to study correlations between tests measuring varied abilities presumed to reflect the underlying attribute of intelligence
Two-factor theory of intelligence
  • Spearman —>
  • Theory of general intelligence
  • General intellectual ability (g) that is partially tapped by all other mental abilities
  • g represents the portion of the variance that all intelligence tests have in common and the remaining portions of the variance being accounted for by specific components (s), or by error components (e) of this general factor.
  • Tests that exhibited high positive correlations with other intelligence tests = highly saturated with g
  • Tests with low or moderate correlations with other intelligence tests = possible measures of specific factors (such as visual or motor ability)
  • Greater g = better predictor of overall intelligence
  • Spearman conceived basis of g factor as some type of general electrochemical mental energy available to the brain for problem solving
  • Group factors —> not as general as g, not as specific as s e.g. linguistic, mechanical, arithmetic abilities
  • Cattell —> two major cognitive abilities
    • Crystallised intelligence (Gc): acquired skills and knowledge that are dependent o exposure to a particular culture as well as formal and informal education (vocabulary, for example), retrieval of info and application of general knowledge
    • Fluid intelligence (Gf): Nonverbal, relatively culture-free, and independent of specific instruction (such as memory for digits)
  • Horn proposed addition of several factors (look on slides) —> some are vulnerable abilities (decline with age and tend not to return to perjury levels after brain damage), some are maintained abilities (not decline with age and may return to perjury levels following brain damage)

Carroll’s Three Strata Theory

The CHC model

  • No g in CHC model
  • 10 broad stratum abilities
  • 70 or more narrow abilities
  • Each broad stream ability subsumes two or more narrow-stratum abilities
  • g not employed in model because it lacked utility in psychoeducational evaluations

The Information-Processing View

  • Focuses on mechanisms by which information is processed —> HOW rather than what
  • Simultaneous processing: info is integrated at one time
  • Successive (sequential processing): each bit of info is individually processed in sequence
  • Sequential processing logical and analytical; piece by piece and one piece after another, info is arranged and rearranged so that it makes sense e.g. anticipating who the murderer is while watching Law and Order
  • Simultaneous processing is synthesised —> info is integrated and synthesised at once and as a whole e.g. looking at artwork
  • PASS model of intellectual functioning – planning, attention, simultaneous, successive

Sternberg —> triarchic theory of intelligence

  • Three principle elements
    • Metacomponents: planning what one is going to do, monitoring what one is doing and evaluating what one has done upon completion
    • Performance components: administer the instructions of metacomponents
    • Knowledge acquisition components: involved in learning how to do something in the first place
  • Successful intelligence : gauged by the extent to which one effectively adapts, shares, shapes, and selects environments in a way that conforms to both personal and societal standards of success

Achieving success in an culture thought to depend on one’s analytic, creative, and practical abilities, as well as an overall ability to capitalise on strengths and to compensate for shortcomings

MEASURING INTELLIGENCE

Entails sampling an examinee’s performance on different types of tests and tasks as a function of developmental level.

Types of tasks used in intelligence tests

Infancy: measuring sensorimotor development e.g. nonverbal motor responses such as turning over, lifting the head, sitting up, following a moving object with the eyes, imitating gestures

Older child: verbal and performance abilities

Mental age: chronological age equivalent of one’s performance on a test or subtest

According to Wechsler, adult intelligence scales should tap abilities such as retention of general info, quantitative reasoning, expressive language and memory, and social judgment —> many tasks the same on adult and children tests, although the content of specific items may vary

INTELLIGENCE: SOME ISSUES

Nature vs. Nurture

  • Measured intellectual ability an interaction between (1) innate ability and (2) environmental influences
  • Seventeenth century – Preformationist —> all living organisms are preformed at birth (i.e. intelligence preformed) and cannot be improved upon
  • Predeterminism: one’s abilities are predetermined by genetic inheritance and no amount of learning or other intervention can enhance what has been genetically encoded to unfold in time
  • Galton believed that genius was hereditary -> based on intelligence tests and family histories, minimised role of environmental enrichment
  • Identical twins reared apart still show remarkably similar test scores, but not as similar as if they had been reared together
  • Children born to poverty-stricken parents but then adopted by better educated, middle class families tend to have higher intelligence scores than counterparts who are not adopted by families of a higher SES
  • Natural mothers with the higher IQs tend to have the children with the higher IQs, irrespective of the family in which the adopted child is raised
  • Level of parental education important in predicting IQ

Verbal, perceptual and image rotation (VPR) model

  • intelligence and related abilities have a very strong basis in genetics
  • hierarchical
  • g factor that contributes to verbal, perceptual and image rotation abilities as well as to eight more specialised abilities

Proponents of nurture side of debate

  • crucial importance of factors such as prenatal and postnatal environment, SES, educational opportunities, parental modelling with respect to intellectual development

Inheritance and interactionism

 

Interactionism: intelligence, as measured by intelligence tests, is the result of the interaction between heredity and environment

  • Interactionist view —> people inherit an intellectual potential
  • How much of that genetic potential is realised depends partially on the type of environment in which it is nurtured • Extremely optimistic
  • ‘We are free to become all that we want to be”
  • Differential impact of hereditary and environment as a result of one’s developmental stage
  • Hereditary influence on intelligence increased from 41% in childhood, to 55% in adolescence, and to 66% in late adolescence and early adulthood
  • Possible explanation: as they age, people increasingly modify their environment to complement genetic tendencies i.e. “we create experiences that suit our genes”

Stability of intelligence

  • Intelligence seems to be stable for much of one’s adult life
  • Young adult intelligence most important determinant of cognitive performance as an older adult
  • In later adulthood, after age 75, a decline in cognitive abilities has been noted

The construct validity of tests of intelligence

  • Essential to know how the test developed defined intelligence

Other issues

The Flynn Effect

  • Measured intelligence seems to rise on average, year by year, starting with the year for which the test is normed
  • Not thought to be due to any rise in “true intelligence”
  • Flynn effect: progressive intelligence from the date when the test was first normed
  • Exact amount of the rise in IQ will vary as a function of several factors, such as how culture-specific the items are and whether the measure used is one of fluid or crystallised intelligence.

Personality

  • Binet conceived the study of intelligence as being synonymous with the study of personality
  • Wechsler also believed that all test of intelligence measure traits of personality e.g. drive, energy level, impulsiveness, persistence and goal awareness.
  • Relationship between various personality characteristics and measured intelligence g. aggressiveness with peers, initiative, high need for achievement, competitive striving, curiosity, self-confidence
  • Temperament in infants can affect an infants measured intelligence ability in that irritable, restless children who do not enjoy being held have a negative reciprocal influence on their parents, and perhaps test administrators too —> parents less likely to want to pick such children up all the time and send more time with them —> less likely to engage in activities that are known to stimulate intellectual development, such as talking to them.

Gender

  • Males may have the edge when it comes to g factor of intelligence

Males tend to outperform females in visual spatialisation

  • Girls outperform on language skill related tasks
  • Motor development follows gender-specific developmental course

Family environment

  • Children thrive in a loving home where their safety and welfare are the utmost concern and where they are given ample opportunity for learning and growth
  • Presence of resources, parental use of language, parental expression of concern about achievement, parental expression of concern about achievement, parental explantation of discipline policies in a warm, democratic home environment
  • Divorce may have significant consequences in the life of a child ranging from impaired school achievement to impaired social problem-solving ability.

Culture

  • Culture provides specific models for thinking, acting and feeling
  • People from different cultural groups can have radically different views about what constitutes intelligence
  • Items on an intelligence test tend to reflect the culture of the society where the test is employed
  • Expected subcultures would score lower
  • Desire to create a culture free intelligence test —> if cultural factors can be controlled, then differences between cultural groups will be lessened, effect of culture can be controlled through the elimination of verbal items and the exclusive reliance on nonverbal, performance items
  • Exclusively nonverbal tests of intelligence not lived up to expectations —> not same high level of predictive validity of more verbally loaded tests
  • Intelligence tests differ in the way they are culture-loaded
  • Culture loading: extent to which a test incorporates the vocal, concepts, traditions, knowledge, and feelings associated with a particular culture
  • No test is legitimately culture free —> culture fair instead
  • Culture fair intelligence test: designed to minimise the influence of culture with regard to various aspects of the evaluation procedures, such as minimisation of instructions, item content, responses required of test takers, and interpretations made from the resulting data
  • Culture loading of test tends to involve more of a subjective, qualitative, nonnumerical judgment (as opposed to factor loading – can be quantified)
  • Rationale fro culture-fair tests was to include only those tasks that seemed to reflect experiences, knowledge and skills common to all different cultures
  • Tasks designed to be motivating for all groups
  • Minimise importance of factors such as verbal skills thought to be responsible for lower mean scores of various minority groups
  • Reducing culture loading of intelligence tests seems to lead to a parallel decrease in the value of the test —> lack predictive validity
  • Minority groups still tended to score lower than majority groups

Frustrated by their inability to develop culture fair equivalents of traditional intelligence tests, some test developers attempted to develop equivalents of traditional intelligence tests that were culture specific

  • Still lacked predictive validity
  • Approaches to reduce cultural bias
    • eliminate items
    • few verbal instructions
    • minimise language bias
    • pilot test