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