MENTAL CALCULATION IN AN AUTISTIC SAVANT - A CASE-STUDY

We present a detailed investigation of mental calculation in RH. an au tistic savant. In Experiment 1 RH performed faster anti more accuratel y than control subjects in mentally solving multi-digit multiplication problems. However, we found no evidence that RH employed short-cut st rategies to solve these problems. His response times were consistent w ith application of a left-to-right computational procedure employed by expert calculators. He also responded extremely quickly to 2-digit sq uares, suggesting that he may have memorized the answers. In Experimen t 2 we taught RH a new computational algorithm for converting temperat ures from Celsius to Fahrenheit. RH was able to learn the new algorith m. but required much assistance and made only slight gains with practi ce. RH did not recognize an easy solution strategy based on inverting steps in the conversion algorithm. We suggest that the inflexible natu re of RH's performance may reflect his autistic tendencies coupled wit h limited intelligence.