A group test for the assessment of performance between the hands.

A group performance test of handedness was administered to 1556 undergraduates. This test required subjects to place dots in circles as rapidly as possible. The test was found to be reliable, and to correlate with hand preference. Both hand performance and hand preference measures are skewed in the population as a whole, but the distributions can be adequately fitted by two normal curves, one with a right bias and one with a left bias. These findings suggest that left-handers are a distinct subgroup of the population.