Measuring Intelligence On the average, autistic children scored fully 30 percentile points higher on the nonverbal Raven’s Progressive Matrices Test than they did on the WISC-III, which depends heavily on oral instruction and responses. In contrast, a matched control group of non-autistic children received scores that were essentially identical. Adult participants showed a similar pattern. Although a small-scale study, such results suggest that traditional intelligence tests may underestimate intelligence in autistic children and adults. In fact, one-third of the autistic children scored above the 90th percentile on the Raven’s, but none did so on the WISC-III. One child raised his score 70 percentile points from 24 to 94 percent—putting him in the “highly intelligent” range rather than the “low-functioning” range.