Intelligence (with Tests)

What is Intelligence?

• Francis Galton:
  • Intelligent persons have the best sensory abilities.
  • The more perceptive the senses, the larger the field for judgment and intelligence.
  • Intelligence is a number of distinct processes or abilities assessed by separate tests.
  • Tests of activity or hearing ability are considered intelligence tests.
  • He devised sensorimotor and perception-related tests.
  • First person to publish on the heritability of intelligence
• Alfred Binet:
  • When solving a problem, abilities interact and cannot be separated.
  • Components of intelligence: reasoning, judgment, memory, and abstraction.
• David Wechsler:
  • Intelligence is the aggregate or global capacity to act purposefully, think rationally, and deal effectively with the environment.
  • Composed of elements or abilities which, though not entirely independent, are qualitatively differentiable.
  • Nonintellective factors include conative, affective, or personality traits like drive, persistence, and goal awareness.
• Individual’s potential to perceive and respond to social, moral, and aesthetic values.
  • Best way to measure intelligence is to measure aspects of several “qualitatively differentiable” abilities.
  • Differentiable abilities → verbal factor and performance factor
• Jean Piaget:
  • Intelligence is an evolving biological adaptation to the outside world.
  • As cognitive skills are gained, adaptation increases, and mental trial and error replaces physical trial and error.
  • Cognitive development occurs neither solely through maturation nor solely through learning, psychological structures become reorganized.

Perspectives on Intelligence

• Interactionism:
  • Heredity and environment interact and influence the development of one’s intelligence.
  • Major thread running through the theories of Binet, Weschler, and Piaget
• Louis L. Thurstone:
  • Intelligence is composed of primary mental abilities:
    • Verbal meaning
    • Perceptual speed
    • Reasoning
    • Number facility
    • Rote memory
    • Word fluency
    • Spatial relations

Factor-analytic Theories

• Spearman’s Two-Factor Theory of Intelligence

  • Existence of a general intellectual ability factor (g).
    • g represents the portion of the variance that all intelligence tests have in common
  • Remaining portions of the variance:
    • Specific components (s) are specific to one intellectual activity only.
    • Error components (e).
  • Tests that exhibit high positive correlations with other intelligence tests → highly saturated with g
  • Low or moderate correlations → tests were viewed as possible measures of specific factors (e.g. motor or visual ability)
  • The greater magnitude of g in an intelligence test, the better the test predicted overall intelligence.
  • g factor is the best predictor of overall intelligence.
  • General electrochemical mental energy available to the brain for problem solving.
  • Associated with facility in thinking of one’s own experience and in making observations and extracting principles (analogous to postformal thought of neo-Piagetians).
  • Abstract reasoning problems were thought to be the best measures of g in formal tests.

• Horn & Cattell

  • Two major types of cognitive abilities:
    • Crystallized intelligence (Gc):
      • Acquired skills and knowledge dependent on exposure to particular culture and formal/informal education.
      • Includes retrieval of information and application of general knowledge.
    • Fluid intelligence (Gf):
      • Nonverbal, relatively culture-free, and independent of specific instruction.
      • “Street smart”
  • Horn proposed additional factors:
    • Visual processing (Gv)
    • Auditory processing (Ga)
    • Quantitative processing (Gq)
    • Speed of processing (Gs)
    • Facility with reading and writing (Grw)
    • Short-term memory (Gsm)
    • Long-term storage and retrieval (Glr)
  • Vulnerable abilities: decline with age and tend not to return to preinjury levels.
  • Maintained abilities: tend not to decline with age and may return to preinjury levels following brain damage.

• Three-Stratum Theory of Cognitive Abilities

  • Carroll
    • Top stratum or 3rd stratum → g or general intelligence
    • Second stratum:
      • Fluid intelligence (Gf)
      • Crystallized intelligence (Gc)
      • General learning and memory (Y)
      • Broad visual perception (V)
      • Broad auditory perception (U)
      • Broad retrieval capacity (R)
      • Broad cognitive speediness (S)
      • Processing/decision speed (T)
    • First stratum:
      • Below each ability in the second stratum are “level factors” and/or “speed factors” which are different, depending on the second-level stratum to which they are linked.
      • First stratum is highly specific and is subsumed in second-level strata which in turn is subsumed in general intelligence
    • This is a hierarchical model
    • All of the abilities listed in a stratum are subsumed by or incorporated in the strata above

• Cattell-Horn-Carroll (CHC) Model

  • Blends the Cattell-Horn Theory with Three-stratum theory
    • Similarities:
      • Designation of broad abilities that subsume several narrow abilities
    • Differences:
      • Existence of g factor
        • Carroll → g is third-stratum factor, subsuming the broad, second-stratum abilities
        • Cattell-Horn → g has no place in the model
      • Abilities labeled “quantitative knowledge” and “reading/writing ability” should each be considered a distinct, broad ability (as in the Cattell-Horn theory)
        • Carroll → abilities are first-stratum, narrow abilities

• McGrew-Flanagan CHC Model

  • Features 10 broad stratum abilities over 70 narrow stratum abilities, with each broad-stratum ability subsuming two or more narrow-stratum abilities
    • Broad stratum abilities: Gf, Gc, Gq, Grw, Gsm, Gv, Ga, Glr, Gs, and Gt (decision/reaction time or speed)
  • Makes no provision for the general intellectual ability because it lacked utility in psychoeducational evaluations
  • It doesn’t mean that g does not exist, rather g has no relevance in cross-battery assessment and interpretation

• E.L. Thorndike

  • Intelligence can be conceived in terms of three clusters of ability:
    • Social intelligence: dealing with people
    • Concrete intelligence: dealing with objects
    • Abstract intelligence: dealing with verbal and mathematical symbols
  • Incorporated g into the theory.
  • Defined as the total number of modifiable neural connections or “bonds” available in the brain.
  • One’s ability to learn is determined by the number and speed of the bonds that can be marshaled

Information-Processing View

• Aleksandr Luria
  • Focuses on how the information is processed, rather than what is processed
  • Basic types of information-processing styles:
    • Simultaneous or parallel processing:
      • Information is integrated at once and as a whole.
      • Processing may be described as “synthesized”.
      • Tasks that involve the simultaneous mental representations of images or information involve simultaneous processing
      • Example: map reading and appreciating art in a museum
    • Successive or sequential processing:
      • Each bit of information is individually processed in sequence.
      • Logical and analytic in nature; piece by piece and one piece after another
      • Information is arranged and rearranged so that it makes sense
    • PASS Model of Intellectual Functioning
      • Planning
      • Attention
      • Simultaneous
      • Successive
        • planning → strategy development for problem solving
        • attention/arousal → receptivity to information
        • simultaneous and successive → type of information processing employed

Measuring Intelligence

• Tasks to Measure Intelligence
  • measurement of intelligence entails sampling an examinee’s performance on different types of tests and tasks as a function of developmental level
  • infancy → measuring sensorimotor development
    • measures of infant intelligence rely to a great degree on information obtained from a structured interview with the examinee’s parents, guardians, or other caretakers
  • older children → verbal and performance abilities
    • fund of information, vocabulary, social judgment, language, reasoning, numerical concepts, auditory and visual memory, attention, concentration, and spatial visualization
  • adult intelligence → retention of general info, quantitative reasoning, expressive language and memory, and social judgment
  • tests of intelligence are seldom administered for purposes of educational placement
    • they may be given to obtain clinically relevant information or some measure of learning potential and skill acquisition

Stanford-Binet Intelligence Scales: Fifth Edition (SB-5)

• First Edition
  • major flaws → lack of representativeness of the standardization sample
  • innovations
    • first published intelligence test to provide organized and detailed administration and scoring instructions
    • first test to employ the concept of IQ
    • first test to introduce alternate item → item to be substituted to regular item under specified conditions (such as when test user failed to properly administer the regular item)
• 1937 Revision
  • first revision started revising in 1926 by Lewis Turman and Maud Merrill
  • included the development of two equivalent forms → L for Lewis and M for Maud
  • new types of tasks for use with preschool-level and adult-level testtakers
  • manual contained many examples to aid the examiner in scoring
  • technical advancement in validity and especially reliability
  • criticism → lack of representation of minority groups during the test’s development
  • employed the ratio IQ based on the concept of mental age → age level at which an individual appears to be functioning intellectually as indicated by level of items responded to correctly
  • ratio IQ → ratio of the testtaker’s mental age divided by chronological age, multiplied by 100 to eliminate decimals
• 1960 Revision
  • second revision consisted of only a single form (L-M)
  • included the items considered to be the best from the two forms of the 1937 test with no new items added
  • use of deviation IQ in place of the ratio IQ
    • tables comparison of the performance of the individual with the performance of others of the same age in the standardization sample
    • test performance is converted into a standard score with a mean of 100 and standard deviation of 16
• 1972 Revision
  • third revision quality of standardization sample was criticized
  • manual was vague about the number of minority individuals in the standardization sample
  • overrepresented the West, as well as large urban communities
• Stanford-Binet: Fourth Edition (SB:FE)
  • previously, different items were grouped by age and the test was referred to as an age scale
  • SB:FE has a point scale → test organized into subtests by category of item, not by age at which most testtakers are presumed capable of responding in the way that is keyed as correct
  • manual contained an explicit exposition of the theoretical model of intelligence that guided the revision based on Cattell-Horn model
  • test composite (formerly deviation IQ score) can be obtained
  • test score or index derived from the combination of, and/or mathematical transformation of, one or more subtest scores
• Fifth Edition (SB-5)
  • designed for administration to assessees as young as 2 and as old as 85 (or older)
  • yields a number of composite scores:
    • Full Scale IQ derived from the administration of ten subtests
      • subtest scores have a mean of 10 and SD of 3
    • Abbreviated Battery IQ score
    • Verbal IQ score
    • Nonverbal IQ score
      • note: the three have mean of 100 and SD of 15
  • test yields five Factor Index scores corresponding to each of the five factors that the test is presumed to measure based on Cattell-Horn-Carroll theory

• psychometric properties
  • standardization
    • 4,800 subjects aged 2-85 and above
    • no accommodations were made for persons with special needs
    • persons were excluded from standardization sample if they had limited english proficiency, severe medical conditions, severe sensory or communication deficits, or severe emotional/behavior disturbance
  • reliability
    • internal-consistency reliability for Full Scale IQ and Abbreviated Battery IQ
      • consistently high across age groups
    • test-retest reliability coefficients were high
      • interval was 5-8 days
    • inter-scorer reliability were high
      • items showing especially poor inter-scorer agreement had been deleted during development process
  • validity
    • content validity was established from expert input and empirical item analysis
    • criterion-related validity
      • concurrent validity with SB:FE and Weschler Battery of tests
        • high correlation with SB:FE and less on Weschler tests (presumably because of varying extents that SB-5 and Weschler test tap g)
      • predictive validity was establish with correlations with measures of achievement
    • construct validity
      • it is not generalizable as questions are raised when it comes to applicability in clinical populations
• test administration
  • first, examiner establishes rapport
  • next, the exam formally begins with an item from a routing test
    • task used to direct or route the examinee to test items that have a high probability of being at an optimal level of difficulty
    • consists of object series/matrices and vocabulary subtests → only these subtests are administered when computing for Abbreviated Battery IQ score
    • contain teaching items → designed to illustrate the task required and assure the examiner that the examinee understands
      • not formally scored, and performance on such items in no way enters into calculations of any other scores
    • basal level → base-level criterion that must be met for testing on the subtest to continue
      • example: examinee answers two consecutive items correctly
    • if an when examinees fail a certain number of items in a row, a ceiling level (highest-level item) is said to have been achieved and testing is discontinued
  • for each subtest, there are explicit rules for where to start, reverse, and stop (or discontinue)
    • start → at the examinee’s estimated present ability level
    • reverse → examinee scores 0 on the first two items from the start point
    • discontinue → after a certain number of item failures after reversing
  • SB-5 is exemplary in terms of adaptive testing
    • testing individually tailored to the testtaker might entail beginning a subtest with a question in the middle range of difficulty
      • if answered correctly, move to an item of greater difficulty
      • if answered incorrectly, move to an item of lesser difficulty
• scoring and interpretation
  • Process scores on the individual items of subtests are tallied to yield raw scores
  • scorer employs tables found in the manual to convert raw scores to standard scores
  • composite scores are derived from standard scores
  • summary: raw scores → standard scores → composite scores
• test may yield a wealth of valuable information regarding the testtaker’s strengths and weaknesses with respect to cognitive functioning
  • it also provides opportunity for behavioral observation
    • extra-test behavior → supplement formal scores
    • SB-5 record form includes a checklist form of notable examinee behaviors

• note: primary value of such labels is as a shorthand reference in some psychological reports.
  • the skill of the examinee must be described in detail and not be limited to only labels

Wechsler Tests

• Wechsler-Bellevue I (W-B-I) 1939
  • point scale in which items were classified by subtests rather than by age
  • test was organized into six verbal subtests and five performance subtests
  • all items in the test were arranged in order of increasing difficulty
• W-B-2 was created in 1942 but was never thoroughly standardized
• problems:
  • restricted standardization sample
  • lack of inter-item reliability of subtests
  • too easy items in some subtests
  • too ambiguous scoring criteria for certain items
• Wechsler Adult Intelligence Scale (WAIS) 1955
  • organized into verbal and performance scales
  • scoring yielded a Verbal IQ, Performance IQ, and a Full Scale IQ
• WAIS-R 1981
  • new norms and updated materials
  • manual mandated the alternate administration of verbal and performance tests
• WAIS-III 3rd edition of WAIS published in 1997
  • updated and more user-friendly materials
  • materials were made physically larger to facilitate viewing by older adults
  • some items were added to each of the subtests that extended the test’s floor in order to make the test more useful for evaluating people with extreme intellectual deficits
  • norms were expanded → includes age range of 74 to 89
  • co-normed with Wechsler Memory Scale-Third Edition (WMS-III)
  • yielded a Full scale (composite) IQ as well as four Index Scores
    • Verbal Comprehension
    • Perceptual Organization
    • Working Memory
    • Processing Speed
• WAIS-IV current Wechsler adult scale
  • made up of:
    • core subtest one that is administered to obtain a composite score
      • includes ten subtests:
        • Block Design
        • Similarities
        • Digit Span
        • Matrix Reasoning
        • Vocabulary
        • Arithmetic
        • Symbol Search
        • Visual Puzzles
        • Information
        • Coding
    • supplemental subtest sometimes referred to as optional subtest
      • used for purposes such as providing additional clinical information or extending the number of abilities or processes sampled
      • includes five subtests:
        • Letter-Number Sequencing
        • Figure Weights
        • Comprehension
        • Cancellation
        • Picture Completion
  • a supplemental subtest might be substituted for a core subset if:
    • the examiner incorrectly administered a core subset
    • the assessee had been inappropriately exposed to the subtest items prior to their administration
    • the assessee evidenced a physical limitation that affected their ability to effectively respond to the items of a particular subset
  • compared to older versions, the WAIS-IV has the absence of Picture Arrangement, Object Assembly, Coding Recall, and Coding Copy-Digit Symbol
  • addition of three new subtests:
    • Visual Puzzles → task is to identify parts that went into making a stimulus design
    • Figure Weights → task is to determine what needs to be added to balance a two-sided scale—one that is reminiscent of the “blind justice” type of scale
    • Cancellation → timed subtest calculating Processing Speed Index task is to draw lines through targeted pairs of colored shapes (while not drawing lines through nontargeted shapes presented as distractors)
  • Floor level → WAIS-III (45); WAIS-IV (40)
  • Ceiling level → WAIS-III (155); WAIS-IV (160)

• note: a → core subtests ; b → supplemental subtest
  • General Ability Index (GAI)
    • composite of two composites calculated using Verbal Comprehension and Perceptual Reasoning indexes
  • Cognitive Proficiency Index (CPI)
    • Working Memory + Processing Speed
  • FSIQ, GAI, and CPI → mean = 100; SD = 15

Short Forms of Intelligence Tests

• short form → test that has been abbreviated in length, typically to reduce the time needed for test administration, scoring, and interpretation
  • a sampling of representative subtests is administered particularly when a testtaker has atypically short attention span or other problems that would make administration of the complete test impossible
  • Silverstein four issues of short forms:
    • how to abbreviate the original test
    • how to select subjects
    • how to estimate scores on the original test
    • the criteria to apply when comparing short form with the original
  • Ryan and Ward advised that scores reported should have “Est” next to it as an indication that the reported value is only an estimate
  • Wechsler Abbreviated Scale of Intelligence (WASI) 1999
    • two-subtest form → Vocabulary and Block Design
      • takes about 15 minutes to administer
    • four-subtest form → Vocabulary, Block Design, Similarities, and Matrix Reasoning
      • takes about 30 minutes to administer
      • yields measures of Verbal IQ, Performance IQ, and Full Scale IQ
    • WASI-2 published in 2011
      • increased linkage and usability with other Wechsler tests
      • more user-friendly materials
      • increased psychometric soundness
      • users strongly cautioned that reduced clinical accuracy as compared to the use of a full-length test may be expected to result

Group Tests of Intelligence

• screening tool → instrument or procedure used to identify a particular trait at a gross or imprecise level
  • data derived may be explore more in depth by more individualized methods of assessment
  • Military
    • Army Alpha Test → administered to army recruits who could read
      • contained general information questions, analogies, and scrambled sentences to reassemble
    • Army Beta Test → administered to foreign-born recruits with poor knowledge of English or to illiterate (could not read a newspaper or write a letter home)
      • contained mazes, coding, and picture completion → draw in the missing element of the picture
    • Army General Classification Test (AGCT) → during the second world war
    • Officer Qualifying Test → admissions test to Officer Candidate School
    • Airman Qualifying Exam → given to all U.S. airforce volunteers
    • Armed Forces Vocational Aptitude Battery (ASVAB) → prospective new recruits in all the armed services
  • School
    • California Test of Mental Maturity
    • Kuhlmann-Anderson Intelligence Tests
    • Henmon-Nelson Tests of Mental Ability
    • Cognitive Abilities Test
    • Otis-Lennon School Ability Test (OLSAT)
      • first group intelligence test used in U.S. schools
      • measures abstract thinking and reasoning ability
      • assists in school evaluation and placement-decision making
      • yields Verbal and Nonverbal score indexes and an overall School Ability Index (SAI)

Other Measures of Intellectual Abilities

• cognitive style → psychological dimension that characterizes the consistency with which one acquires and processes information

  • field dependence vs field independence dimension
  • reflection vs impulsivity dimension
  • visualizer vs verbalizer dimension

• creativity measures

  • originality → ability to produce something that is innovative or nonobvious
  • fluency → ease with which responses are reproduced and is usually measured by the total number of responses produced
  • flexibility → variety of ideas presented and the ability to shift from one approach to another
  • elaboration → richness of detail in a verbal explanation or pictorial display

• Guilford’s Structure-of-Intellect Model

  • convergent thinking
    • thought process required on most achievement tests
    • deductive reasoning
      • process that entails recall and consideration of facts as well as a series of logical judgments to narrow down solutions and eventually arrive at one solution
  • divergent thinking
    • reasoning process in which thought is free to move in many different directions, making several solutions possible
    • requires flexibility of thought, originality, and imagination
    • much less emphasis on recall of facts

Issues in the Assessment of Intelligence

• Culture and Measured Intelligence
  • because different cultural groups value and promote different types of abilities and pursuits, testtakers from different cultural groups can be expected to bring to a test situation differential levels of ability, achievement, and motivation
  • to the extent that a score on a test reflects the degree to which testtakers have been integrated into the society and culture, it would be expected that members of subcultures would score lower
  • culture-free intelligence test
    • assumption: if cultural factors can be controlled then differences between cultural groups will be lessened
    • the effect of culture can be controlled through the elimination of verbal items and exclusive reliance on nonverbal, performance items
    • culture loading → extent to which a test incorporates the vocabulary, concepts, traditions, knowledge, and feelings associated with a particular culture
  • culture-fair intelligence test
    • test or assessment process designed to minimize the influence of culture with regard to various aspects of the evaluation procedures, such as administration instructions, item content, responses required of testtakers, and interpretations made from the resulting data
    • includes only those tasks that seemed to reflect experiences, knowledge, and skills common to all different cultures
    • tended to be non-verbal and to have simple, clear directions administered orally by the examiner
    • typically consisted of assembling, classifying, selecting, or manipulating objects and drawing or identifying geometric designs
    • lack predictive validity
• Flynn Effect
  • James R. Flynn
    • intelligence inflation
      • progressive rise in intelligence test scores that is expected to occur on a normed test
    • intelligence from the date when the test was first normed
      • measured intelligence seems to rise on average, year by year, starting with the year for which the test was normed