WAIS-IV Clinical Use and Interpretation

Scientist-Practitioner Perspectives

Lawrence G. Weiss, Donald H. Saklofske, Diane Coalson, Susan Engi Raiford

• Publisher: Academic Press
• Year: 2010
• eBook ISBN: 9780080963211
• Topic: Psychology
• Subtopic: Educational Psychology
• Index: Psychology

Published in August of 2008, WAIS–IV is the most widely used intelligence test for adults in the world. Substantive changes were made to the WAIS-IV from the WAIS-III leaving clinicians with questions as to how to use and interpret the measure effectively. Written by the creators of the new test, this book serves as the ultimate insider's guide to the new test, providing users with the kind of access to norms and data that would be unavailable to any subsequent book on clinical use of this measure. The book discusses the changes made between 3rd and 4th editions along with an FAQ and answers about use and interpretation. The reader is instructed how to interpret composite scores, and everything needed to use and interpret two entirely new composite scores: the General Ability Index (GAI), and the Cognitive Proficiency Index (CPI). This information does NOT appear in the manual accompanying the test. The second section of the book focuses on WAIS–IV use and interpretation with special clinical applications and populations, including with multicultural clients, in neuropsychological settings, with individuals experiencing psychological disorders, and with older adults. The editors and chapter authors have exclusive access to proprietary WAIS–IV data to run advanced analyses and provide information beyond what is offered in the WAIS-IV manual. - Provides practical advice on scoring and administration - Facilitates understanding WAIS-IV use with special populations - Describes use of the WAIS-IV with WMS-II

PART I

THE WAIS-IV: DEVELOPMENTAND FOUNDATIONS

CHAPTER 1 WAIS-IV

Advances in the Assessment of Intelligence

Diane L. Coalson ¹ , Susan Engi Raiford ¹ , Donald H. Saklofske ² , Lawrence G. Weiss ¹

1 Pearson Assessment, San Antonio, Texas, USA

2 Division of Applied Psychology, University of Calgary, Calgary, Alberta, Canada

Introduction

The Wechsler Adult Intelligence Scale – Fourth Edition (WAIS-IV; Wechsler, 2008a) reflects the culmination of over 70 years of progressive revisions to the Wechsler line of adult intelligence measures. It is ironic that the very mention of historical foundations of the Wechsler scales contributes to the misperception that the scales are outdated. In fact, Wechsler's foresight in defining intelligence in practical terms has allowed the very flexibility needed for ongoing revisions to his intelligence scales in light of advances in theory, research, and the measurement of intelligence. The most recent editions of the Wechsler intelligence scales have involved dramatic changes based on burgeoning research advances in neuropsychology, cognitive neuroscience, and contemporary intelligence theory, as well as increasing sophistication in psychological measurement. Despite these substantial innovations, some critics perpetuate the myth that the Wechsler intelligence scales are outdated or atheoretical (Kamphaus, 1993; Shaw, Swerdlik, & Laurent, 1993; Flanagan & Kaufman, 2004). We respectfully disagree and, for this reason, elaborate somewhat on Wechsler's views about intelligence and the progressive adaptations to his intelligence scales in light of contemporary theory and research. We are hopeful that the historical references, often from Wechsler's own writings, will help to clarify the theoretical foundations of the Wechsler intelligence scales, in Wechsler's time and in ours.

Wechsler's theory of intelligence: past and present

Much has been written about the historical foundations of intelligence testing, and the reader is referred to these sources (for example, Thorndike, 1990; Sternberg, 2000; Goldstein & Beers, 2003; Tulsky, et al., 2003) to gain a greater appreciation and understanding of the evolution of current assessment practices. The introductory chapters of the Tulsky et al. (2003) book provide an excellent overview of the history of intelligence and memory testing, including the origins of many subtests that continue to appear in the most recent editions of the Wechsler intelligence and memory scales. Appendix material in the Tulsky et al. (2003) book provides brief biographical sketches of pioneers in the field of intelligence testing, and the influence they had on Wechsler's ideas about intelligence test development.

David Wechsler entered the field of psychology at an incredibly exciting and innovative time. Preliminary attempts to measure intelligence by Galton and Cattell had spawned an interest in defining the construct of intelligence, most notably represented by the series of debates between Charles Spearman and Edward L. Thorndike on the structure of intelligence and their differing views regarding a general intelligence factor. Advances in psychometric theory and application, and particularly factor analysis, allowed for a closer evaluation of the content represented by the various intelligence measures.

At the time that Wechsler developed the Wechsler-Bellevue Intelligence Scale – Form I (WB-I; Wechsler, 1939) there were two primary theories of intelligence, represented by the views of Spearman and Thorndike. As clarified through their historical debates in the early part of the century, Spearman believed there was a general factor of intelligence, “g,” that determined an individual's ability to perform any mental task. Based on evidence indicating low correlations among some intelligence measures, Spearman revised his original theory and added specific factors to the structure of intelligence (Spearman, 1904). Thus, Spearman's revised theory (1904) asserted that intelligence was composed of both a general and specific factors, with the general factor reflecting overall intelligence, and the various specific factors reflecting more specialized abilities that shared some variance with the general factor. In contrast, Thorndike did not support the position of a general factor in the structure of intelligence, instead asserting that there were different kinds of intelligence, such as abstract, social, and practical intelligences.

Although some may have assumed that Wechsler agreed with Spearman's view of “g” based on the inclusion of a summary score (i.e., the Full Scale IQ) to represent general intelligence, he included aspects from both theoretical camps in his (1939) definition of intelligence as:

the aggregate or global capacity of the individual to act purposefully, to think rationally, and to deal effectively with his [or her] environment. It is global because it characterizes the individual's behavior as a whole; it is an aggregate because it is composed of elements or abilities which, though not entirely independent, are qualitatively differentiable. ( Wechsler, 1939 : 3)

Thus, the definition clearly supports the existence of a general (or global) intelligence, but also asserts that general intelligence is composed of qualitatively different abilities. Wechsler further argued that these specific abilities included both cognitive abilities and other, non-intellective abilities such as drive, persistence, temperament, and curiosity, an interesting mix of other cognitive, personality, and conatative factors (Wechsler, 1950). Although he was not successful at incorporating measures of non-intellective factors into his intelligence scales during his lifetime, he was successful at selecting measures of cognitive ability (e.g., verbal comprehension, perceptual organization, working memory) for his scales that were later found to be important factors of intelligence (Carroll, 1993).

Perhaps it is the resilience of Wechsler's practical definition of intelligence that leads others to assert that his intelligence scales are outdated. Wechsler's original definition of intelligence remained unchanged throughout subsequent editions of his companion text for his adult intelligence scales, The Measurement of Adult Intelligence (Wechsler, 1939, 1941, 1944, 1958), as well as peer-reviewed journal articles (Wechsler, 1950, 1975). In fact, Wechsler's original definition continues to appear in the latest revisions of his intelligence scales (Wechsler, 2003, 2008a), as it is still relevant and practical in light of contemporary views on intelligence. Results of the most comprehensive factor-analytic investigations of intelligence measures to date suggest overwhelming evidence for a general intelligence factor at the apex of a hierarchical intelligence construct that is composed of a set of related, but distinguishable, abilities (Carroll, 1993, 1997). This finding has been replicated in cross-cultural studies of both the child and adult versions of the Wechsler intelligence tests (see, for example, Georgas, Weiss, van de Vijver, & Saklofske, 2003). Research on the predictive validity of general intelligence suggest that it is superior to more narrow cognitive domains in predicting such important life outcomes as academic and occupational performance (Deary, 2009; Gottfredson, 2009). Factor-analytic results also suggest that general intelligence is composed of 8–10 broad domains of intelligence that are, in turn, composed of more specific abilities (Carroll, 1993; Horn & Noll, 1997). In light of these cumulative findings, subsequent revisions of the Wechsler scales have expanded measures of additional cognitive domains (e.g., fluid reasoning, working memory, processing speed) while continuing to provide a reliable estimate of general intelligence, the Full Scale IQ (FSIQ).

Wechsler's foresight in distinguishing between intelligence and the cognitive abilities he used to measure it allowed him to avoid one of the major fallacies ...

Table of contents

• Cover
• Title Page
• Copyright
• Dedication
• List of Contributors
• Foreword
• Preface
• Part I: The WAIS-IV: Developmentand Foundations
• Part II: The WAIS-IV: Clinical Use and Interpretation in Context
• Index