Meaningful versus Abstract Stimuli

Picture Completion and Picture Arrangement use pictures of people and things, whereas Matrix Reasoning, Block Design, Symbol Search, and Digit Symbol-Coding require the perception and processing of abstractions: complex designs, simple designs, and numbers. Object Assembly doesn't fit neatly into either category. For the WISC-III, we classified Object Assembly with the two "Picture" subtests because the final product to be assembled is meaningful (Kaufman & Lichtenberger, 2000). However, the first two WISC-III puzzles are named for the child, and almost all puzzles have at least one large piece that makes the object to be constructed obvious to all but the severely impaired. For the WAIS-III, none of the puzzles is named, and some individuals are unaware of the nature of what they are constructing for the Elephant and, especially, the Butterfly. Consequently, we have categorized Object Assembly as measuring visual perception of meaningful stimuli but only Picture Completion and Picture Arrangement are categorized as measuring visual perception of complete meaningful stimuli. The WAIS-III puzzle pieces may be seen as meaningful by many people, but are likely to be processed as abstractions by others, for example, by some neurological patients because they are not "complete" meaningful stimuli.

Because of the complexity of the Performance tasks in general—Matrix Reasoning, Block Design, Symbol Search, and Digit Symbol-Coding in particular—it is necessary to cross-validate any hypothesis regarding an individual's discrepancy between perceiving or processing meaningful versus abstract stimuli. More likely than not, the person will evidence better performance in mean ingful than abstract stimuli; the reverse pattern is not as explainable from a neuropsychological framework and is less valuable in a diagnostic sense. If Matrix Reasoning, Block Design, Symbol Search, and Digit Symbol-Coding are high relative to the "picture" dyad, other explanations may be necessary. Possibly the person is threatened by the social stimuli, especially in Picture Arrangement, and feels more comfortable with neutral stimuli. Or the difference may be more related to the imitative aspect of Digit Symbol-Coding and Block Design (both involve reproduction of models), a skill that may be better developed than problem solving without a model.

The latter hypothesis requires consideration of Object Assembly rather than Picture Completion performance. Picture Arrangement and Object Assembly are each nonverbal-reasoning, problem-solving tasks; unlike Block Design and Digit Symbol-Coding, neither reasoning subtest provides the individual with a model to copy. Some individuals perform better when a model is provided, and others do better without one. When Picture Arrangement pairs with Object Assembly (or also with Matrix Reasoning), in contrast to a different level of performance on the two nonverbal imitative tasks, the examiner should entertain a reasoning versus imitation hypothesis. Additional support for this hypothesis may reside within the configuration of the Verbal profile. An individual with better imitative than reasoning skills within the visual-motor sphere, for example, might well display a comparable profile of high memory-low reasoning within the auditory-vocal channel.

But, when the pattern does not involve Object Assembly, and the nonverbal configuration clearly implies a deficiency in perceiving or processing abstract stimuli compared to meaningful stimuli, verification of the hypothesis can take several forms. Is there any evidence of brain damage, either diffuse or in the posterior regions of the right cerebral hemisphere? Did the individual have difficulty on Verbal subtests that use numerical symbols (Digit Span, Arithmetic, Letter-Number Sequencing)? Did he or she do better on the more meaningful, context-related Verbal subtests (Information, Comprehension) than on the ones that require responses to isolated verbal concepts (Vocabulary, Similarities)? Matrix Reasoning can help assess if a person is able to reason effectively with abstract stimuli. If Matrix Reasoning scores are discrepant from poor performance on Block Design and Digit Symbol-Coding, some other variable (speed, coordination, imitation), but not the abstractness of the stimuli, may have affected performance.

Understanding And Treating Autism

Understanding And Treating Autism

Whenever a doctor informs the parents that their child is suffering with Autism, the first & foremost question that is thrown over him is - How did it happen? How did my child get this disease? Well, there is no definite answer to what are the exact causes of Autism.

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