Differential effects on verbal-performance achievement levels on the WAIS-R as a function of progressive error rate...

One hundred seventy-eight subjects participated in a study to measure the degree of selective subtest decline on the WAIS-R as a function of increased error rate on the Memory-for-Designs Test. The data show that there is an initial, significant decline in the verbal knowledge component of the verbal scale as error rate on the MFD progresses. Performance factors are only significantly related to error rate on the MFD when the latter are maximized.