Chapter 10-The Wechsler Intelligence Scales: WAIS-IV, WISC-V, and WPPSI-IV (Exam 2)

Point scale concept

-By arranging items according to content and assigning a specific number of points to each item, Wechsler constructed an intelligence test that yielded an overall score but also scores for each content area -the point scale concept allowed Wechsler to devise a test that permitted an analysis of the individual's ability in a variety of content areas

WAIS-IV

-Wchsler had a similar definition of intelligence as Binet -Wechsler believed that intelligence comprised specific elements that one could individually define and measure and they were interrelated -intelligence comprises several specific interrelated functions or elements and that general intelligence results form the interplay of these elements -measured separate abilities, which Binet had avoided din adopting the concept of general mental ability Subtests: -Vocabulary: Vocabulary is very stable and less vulnerable than other aspects of intelligence. Relatively stable estimate of general verbal intelligence and can be used to evaluate baseline or premorbid intelligence -Similarities: paired times of increasing difficulty. The subject must identify the similarity between the items in each pair. Some items definitely require the subject to think abstractly. -Arithmetic: 15 relatively simple problems in an increasing order of difficulty. Concentration, motivation, and memory are the main factors underlying performance -Digit span: requires the subject to repeat digits given at the rate of one per second forward and backward which measures short-term auditory memory -Information: items appear in order of increasing difficulty and involves both intellective and non-intellective components including the abilities to comprehend instructions, follow directions, and provide a response -Comprehension: Three types of questions. Ask the subject what should have been done in a given situation, asks the subject to provide a logical explanation for some rule of phenomenon, and asks the subject to define proverbs. -Letter-Number sequencing: supplementary on the working memory test and may be used as a supplement for additional information about the person's intellectual functioning. Made up of items where the individual is asked to reorder lists of numbers and letter in relation to working memory and attention -Digit symbol-coding: requires the subject to copy symbols. The subject has 120 seconds to copy as many symbols as possible which examine learning an unfamiliar task, visual-motor dexterity, degree of persistence, and speed of performance. -Block design: nine variously colored blocks and a booklet with pictures of the blocks arranged according to a specific geometric design or configuration. The subject must arrange the blocks to reproduce increasingly difficult designs which requires the subject to reason, analyze spatial relationships, and integrate visual and motor functions. -Matrix reasoning: included in an effort to enhance the assessment of fluid intelligence. The subject is presented with nonverbal, figural stimuli. The tag is to identify a pattern of relationship between the stimuli. This subtest is a good measure of information processing and abstract-reasoning skills -The symbol search: A relatively new subtest and adde din recognition of there ole of speed of information processing in intelligence. The subject is shown two target geometric figures and has to search from a set of five additional search figures and determine whether the target appears in the search group. The faster a subject performs this task, the faster his or her information-processing speed will be

The performance scale concept

-Wechsler included an entire scale that provided a measure of nonverbal intelligence: a performance scale -Wechsler's performance scale consisted of tasks that require a subject to do something rather than merely answer questions -The original Wechsler scale included two separate scales with a verbal scale and a performance scale -Wechsler's new scale was the first to offer the possibility of directly comparing an individuals'v verbal and nonverbal intelligence -can measure intelligence but also observe behavior

Standardization

-a stratified sample of 2200 adults divided into 13 age groups and 13 speciality groups -stratified according to gender, race, education, and geographic region

Reliability

-average coefficients across age levels are .98, .96, .95, .94, and .90 -overall standard error of measurement of 2.16 and 2.85 -the error is a bit higher for the other indexes

WISC-V

-can be administered adds core day two coordinating iPads which is faster and more efficient -follows the model already seen in the WAIS-IV and data continue to reveal a hierarchical structure with the top being FSIQ -verbal comprehension, visual spatial, fluid reasoning, working memory, and processing speed -each index is associated with at least two subtest scores -five ancillary scales, each base don two or more subtests -quantitative reasoning, auditory working memory, nonverbal, general ability, and cognitive processing -complementary scales: naming speed, symbol translation, and storage and retrieval -special group studies which support its validity

The Wechsler intelligence scales

-challenged Binet's supremacy as a measure of human intelligence -did not directly measure nonintellective factors, but it took these factors into careful account in its underlying theory -deviated from many of the Binet scale's central concepts -Binet's scale not appropriate for adults -Binet's scale emphasized speed and mental age norms didn't apply to adults -didn't consider that intellectual performance could deteriorate as a person grew older

Evaluation of the Wechsler Adult Scales

-extensively used as a measure of adult intelligence -four index components and full-scale IQ are highly reliable -the reliability of the individual subtests is lower

Index comparisons

-nonverbal measures add in the interpretation of the verbal measures -not appropriate to make sweeping generalizations about the meaning of index discrepancies and should provide a warning as new research begins to look at comparisons among index scores

FSIQ

-obtained by summing the age-corrected scaled scores of all four index composites

Pattern analysis

-one evaluates relatively large differences between subtest scaled scores -analysis of patterns must be done cautiously and used to generate hypothesis which should be corroborated or refuted by other sources of data

Raw to scaled scores

-raw scores can be converted to standard or scaled scores with a mean of 10 and a standard deviation of 3 -inferential norming is used -able to derive reference group norms which allow the test user to compare subjects at the subtest level -the four composite index scales are then derived by summing the core subtest scores

Validity

-rests heavily on its correlation with earlier versions of the test

The WPPSI-IV

-scale for children 4-6 years of age -five composites -now covers age ranges 2-6 -gives the test user the option of using more or less subtests depending on how complete an evaluation is needed and how young the child is -younger children required less testing -based on the hierarchical model with general mental ability at the top and reflected in the full-scale IQ -compatible with measures of adaptive functioning and achievement -well constructed, excellent reliabilities, and well grounded in modern theory -considerable interest in the new working memory index but the larger issues relates to the stability and validity of all three indexes -general "g" factor as represented by full-scale IQ accounted for more variable in every subtest than did its corresponding domain-specific factor -the "g" factor accounted for more total and common variance than all domain-specific factors combined

Index scores

-verbal comprehension, perceptual organization, working memory, and processing speed -verbal comprehension index is like crystallized intelligence -perceptual reasoning consists of visual puzzles, block design, and matrix reasoning which is fluid intelligence -working memory: information that we actively hold in our minds in contrast to stored knowledge or long-term memory -processing speed index attempts to measure how quickly your mind works