The relationship between intellectual ability and adult performance on the Trail Making Test and the Symbol Digit Modalities Test.

Subjects between the ages of 18 and 30 were divided in groups based on their Satz-Mogel Wechsler Adult Intelligence Scale-Revised Full Scale IQs: (a) Borderline (70 to 79); (b) Low Average (80 to 89); (c) Average (90 to 109); (d) High Average (110 to 119); (e) Superior (120 to 129). Each subject was administered the Trail Making Test (Forms A and B) and the written version of the Symbol Digit Modalities Test. A significant effect for IQ emerged. The low ability subjects were, in the main, significantly different from the higher ability subjects. No gender differences were found.