Intelligence Testing

When to Use IQ Testing Placement decisions Retardation Giftedness Determination of cognitive strengths and weaknesses (Tx planning) Establishing a baseline Prediction of job performance Part of neuropsych assessment

Views of Intelligence “g” models and factor analysis Fluid vs. crystallized Multiple intelligences - Sternberg - Gardner

Assumptions of the IQ Model “g” factor exists IQ is not innate or fixed Not an achievement test Tests are reasonably culture-fair Scores predict outcomes, but not perfectly Scores must be interpreted by a skilled professional in a context

Wechsler on Intelligence “Intelligence... Is the aggregate or global capacity of the individual to act purposefully, to think rationally, and to deal effectively with his environment... It is composed of elements or abilities which, though not entirely independent, are qualitatively differentiable.”

Limitations of Wechsler Scales Assumes a “g” model Applicability to minorities Complicated scoring subject to errors Subjectivity in scoring some responses Environmental influences affect scores (e.g., effort, anxiety)

WAIS-III Subtests Performance Verbal Picture Compltn Vocabulary Digit Symbol Similarities Block Design Arithmetic Matrix Reasoning Digit Span Pic Arrangement Information Symbol Search* Comprehension Object Assembly* Letter-Number Seq

WISC-III Subtests Performance Verbal Picture Compltn Information Coding Similarities Pic Arrangement Arithmetic Block Design Vocabulary Object Assembly Comprehension Symbol Search* Digit Span* Mazes*

Levels of Intelligence IQ Score Classification % incl 130 + Very Superior 2.1 120-129 Superior 8.3 110-119 High Average 16.1 90-109 Average 50 80-89 Low Average 14.8 70-79 Borderline 6.5 69 - Extremely Low 1.9 (WAIS-III) Intellectually Deficient (WISC-III)

Steps in Interpreting an IQ Test Know your referral question Gather appropriate background data Evaluate global scores: Full Scale, Verbal & Performance, Index Scales Evaluate subtests and scatter Intra and inter-individual differences Interpret significant differences Integrate behavioral observations