Spatial complexity and hand usage on the Block Design Test

The Block Design test is a task utilizing spatial ability, on which subjects are required to arrange red and white blocks in a pattern similar to one presented on a stimulus card. 69 right-handed subjects were presented a series of trials which varied in difficulty or spatial complexity. The amount of time that each subject's hand was in contact with the blocks during each of the reproduction attempts was recorded. Analysis of these times shows that subjects use their right hands with greater frequency only on tasks of low and moderate spatial complexity. This preference is not present on tasks of high spatial complexity. Interpretations of this finding are offered.