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Intelligence and its Measurement

What is Intelligence?

  • Intelligence: a multifaceted capacity that includes the abilities to
    • acquire and apply knowledge
    • reason logically, plan effectively, and infer perceptively
    • grasp and visualize concepts
    • find the right words and thoughts with facility
    • cope with and adjust to novel situations
  • However, intelligence is not limited to this description and this list should be considered a point for reflection on one’s own personal definition
  • Intelligence as Defined by the Lay Public
    • Sternberg and associates sought to shed light on the lay public’s definition of intelligence, as well as its definition by psychologists
    • differences between laypeople’s definitions and that of experts included motivation (with experts tending to emphasize motivation) and the interpersonal aspects of intelligence (as emphasized in the lay public’s definition)
    • Siegler and Richards (1980) asked developmental psychology students to list behaviors associated with intelligence in infancy, childhood, and adulthood
    • different conceptions of intelligence as a result of development were noted
    • Yusen and Kane (1980) found that notions of intelligence emerge as early as first grade
    • Younger children tended to emphasize interpersonal skills while older children emphasized academic skills
  • Intelligence as Defined by the Experts
    • Sir Francis Galton was the first person to publish on the heritability of intelligence
    • Galton (1883) believed that the most intelligent persons were equipped with the best sensory abilities
    • by such logic, test of visual acuity or hearing ability are measurements of intelligence
    • Galton developed many sensorimotor and perception-related tests by which he attempted to measure his definition of intelligence
    • Alfred Binet did not define intelligence explicitly but instead described various components of intelligence, including reasoning, judgment, memory, and abstraction
    • Binet and a colleague criticized Galton’s approach to intellectual assessment and instead called for more complex measurements of intellectual ability
    • While Galton argued that intelligence consisted of distinct processes that could be assessed only by individual tests, Binet viewed intelligence as inseparable abilities that required complex measurements to determine
  • David Wechsler (1958) conceptualized intelligence as “the aggregate … capacity of the individual to act purposefully, to think rationally, and to deal effectively with his environment. It is composed of elements abilities which … are qualitatively differentiable
    • Wechsler was of the opinion that the best way to measure intelligence was by measuring several “qualitatively differentiable” abilities, which were verbal - or performance-based in nature
    • The Wechsler-Bellevue (W-B) Scale provided the calculation of a verbal IQ and a performance IQ
  • Jean Piaget focused his research on the development of cognitive abilities in children
    • Piaget defined intelligence as an evolving biological adaptation to the outside world; a consequence of interaction with the environment, psychological structures become reorganized
    • According to Piaget, as individual stages are progressed through, the child has experiences within the environment that requires some form of cognitive organizations in a schema
    • Schema: a mental structure that, when applied to the world, leads to knowing or understanding
    • learning was hypothesized to occur through 2 operations
    • Assimilation: the active organization of new information into an existing schema
    • Accomodation: the adjustment of an existing schema to new information
    • According to Piaget, there are 4 periods of cognitive development, each representing a more complex form of cognitive reorganization
    • these stages range from the sensorimotor period in infancy to the formal operations period in adolescence
  • Interactionism: the mechanism by which heredity and environment are presumed to interact and influence the development of intelligence
  • Factor-Analysis Theories of Intelligence: focus squarely on identifying the ability or groups of abilities deemed to constitute intelligence
    • Factor Analysis: a group of statistical techniques designed to determine the existence of underlying relationships between sets of variables
    • Spearman (1927) postulated the existence of a general intellectual ability factor (g) and specific factors of intelligence
    • g was assumed to afford the best prediction of overall intelligence, best measured through abstract-reasoning problems
    • Many multiple-factor models of intelligence have been proposed
    • Some (Guilford, Thurstone) have sought to explain mental activities by deemphasizing or eliminating any reference to g
    • Gardner developed a theory of 7 intelligences: logical-mathematical, bodily-kinesthetic, liguistic, musical, spatial, interpersonal, and intrapersonal
    • Horn and Cattell developed a theory of intelligence postulating the existence of 2 major types of cognitive abilities
    • Crystallized Intelligence (Gc): includes acquired skills and knowledge that are dependent on exposure to a particular culture as well as on formal and informal education
    • Fluid Intelligence (Gf): nonverbal, relatively culture-free, and independent of specific instruction
    • The CHC model integrates the Cattell-Horn and Carroll models, featuring 10 “broad-stratum” abilities and over 70 “narrow-stratum” abilities
    • each broad-stratum ability subsumes 2 or more narrow-stratum abilities
  • Information-Processing Theories: focus on identifying the specific mental processes that constitute intelligence
    • Simultaneous (Parallel) Processing: the integration of information occurs all at once
    • Successive (Sequential) Processing: information is individually processed in a logical sequence

Measuring Intelligence

  • measuring intelligence entails sampling an examinee’s performance on different types of tests and tasks as a function of developmental level
  • In infancy, intellectual assessment consists of measuring sensorimotor development
  • In older, children, intellectual assessment focuses on verbal and performance abilities
  • Adult intelligence scales should tap abilities such as general information retention, quantitative reasoning, expressive language, and social judgment
    • Intelligence tests are rarely administered to adults for purposes of educational placement, but rather to ascertain clinically relevant information or learning potential
  • Mental Age: an index that refers to the chronological age equivalent of one’s performance on a test or subtest
    • many intelligence tests were scores and interpreted with reference to mental age

Intelligence: Some Issues

  • Nature vs Nurture
    • Today most behavioral scientists believe that measured intellectual ability represents an interaction between innate ability and environmental influences
    • Historically, however, this interactionist perspective was not popular.
    • Preformationism: a theory that holds that all living organisms are preformed at birth; all of an organism’s structures, including intelligences, are performed at birth and cannot be improved upon
    • Predeterminism: the doctrine that holds that one’s abilities are predetermined by genetic inheritance and that no amount of learning or other intervention can enhance what has been genetically encoded to unfold
    • Gesell (1929) was a major proponent predeterminism and with twin studies, concluded that “training does not transcend maturation”
      • Gesell believed that neural mechanisms, rather than experience, were most important in the development of intelligence
      • He argued that behavioral patterns are determined by “innate processes of growth” that he likened to maturation
    • Proponents for the “nurture” side of the debate emphasize the importance of factors such as prenatal and postnatal environment, socioeconomic status, educational opportunities, and parental modeling
    • Interactionist models suggest that people inherent a certain intellectual potential, which then depends on the type of environment in which it is nurtured
  • Other Issues
    • Flynn Effect: the progressive rise in intelligence test scores that is expected to occur on a normed intelligence test from the date when the test was first normed
    • Culture
    • Culture provides specific models for thinking, acting, and feeling, enabling people to survive both physically and socially and to master the world around them
    • values may differ radically between cultural groups, and thus individuals from these varying cultures may have radically differing views on what constitutes intelligence
    • items on an intelligence test tend to reflect the culture of the society where the test is employed and thus many theorists have expressed a desire to develop a culture-free intelligence test
    • Culture-free intelligence tests are difficult if not impossible, and thus “culture-fair” intelligence tests began to be developed
    • Culture Loading: the extent to which a test incorporates the vocabulary, concepts, traditions, knowledge, and feelings associated with a particular culture

Test of Intelligence

The Standard-Binet Intelligence Scales

  • the first published intelligence test with clear instructions on use
  • Ratio IQ: the ratio of the testtaker’s mental age divided by his or her chronological age, multiplied by 100 to eliminate decimals

ratio IQ = (mental age/chronological age)*100

  • With the third edition of the Stanford-Binet, the deviation IQ was replaced with the ratio IQ
    • Deviation IQ: a comparison of the performance of the individual with the performance of others in the same age in the standardization sample
  • With the fourth edition, a point scale was implemented which organized subtests by category of item rather than the age at which most testtakers should be able to respond correctly
  • model for the 4th and 5th edition
    • The 5th edition was designed for administration to ages 2 to 85
    • The test yields a composite of scores, including a Full Scale IQ, Abbreviated Battery Score, Verbal IQ Score, and Nonverbal IQ score
  • Fifth Edition
    • Fluid Reasoning (FR)
    • novel problem solving; understanding of relationships that are not culturally bound
      • Nonverbal: object series or matrices
      • Verbal: analogies
    • Knowledge (KN)
    • skills and knowledge acquired by formal and informal education
      • Nonverbal: picture absurdities
      • Verbal: vocabulary
    • Quantitative Reasoning (QR)
    • knowledge of mathematical thinking including no concepts, estimation, problem solving, and measurement
      • Nonverbal: nonverbal QR
      • Verbal: verbal QR
    • Visual-Spatial Processing (VS)
    • ability to see patterns and relationships and spatial orientation as well as the gestalt among diverse visual stimuli
      • Nonverbal: form board
      • Verbal: position and direction
    • Working Memory (WM)
    • cognitive process of temporarily storing and then transforming or sorting information in memory
      • Nonverbal: delayed response
      • Verbal: memory for sentences
    • can be converted into nominal categories designated by cutoff boundaries for quick reference
  • The Wechsler Tests
    • a series of individually-administered intelligence tests to assess the intellectual abilities of people from preschool through adulthood
    • Until recently, all Wechsler scales yielded several possible composite scores, including a full scale IQ (a measure of general intelligence), a verbal IQ, and a performance IQ
    • Wechsler Adult Intelligence Scale, 4th Ed. (WAIS-IV)
    • consists of subtests that are designated as either “core” or “supplemental”
      • Core Subtest: a subtest administered to obtain a composite score
      • Supplemental Subtest: a subtest administered to provide additional clinical information or extend the number of abilities or processes sampled
    • contains 10 core subjects (Block Design, Similarities, Digit Span, Matrix Reasoning, Vocabulary, Arithmetic, Symbol Search, Visual Puzzles, Information, and Coding) and 5 Supplemental Subtests (Letter-Number Sequencing, Figure Weights, Comprehension, Cancellation, and Picture Completion)
  • Wechsler Intelligence Scale for Children, 4th Ed. (WISC-IV)
    • yields a measure of general intellectual functioning (a full scale IQ) as well as 4 index scores: a Verbal Comprehension Index, a Perceptual Reasoning Index, a Working Memory Index, and a Processing Speed Index
    • it is also possible to derive up to 7 process scores
    • Process Score: an index designed to help understand the way the test taker processes various kinds of information
    • for ages 6 through 16 years, 11 months
  • Wechsler Preschool and Primary Scale of Intelligence, 3rd Ed. (WPPSI-III)
    • was developed to assess children and racial minorities
    • includes several subtests, including Matrix Reasoning, Symbol Search, Word Reasoning, and Picture Concepts
    • 4-6 years of age