Hemisphere differences and judgments of simultaneity of brief light flashes

A series of experiments was conducted to investigate the possibility of hemispheric specialization for judgments of the simultaneity of two light flashes. Right-handed subjects adjusted two light flashes until they appeared simultaneous. The comparison of measures derived from the two possible orders of the light flashes suggested that the right hemisphere of right-handed subjects performed the function of ordering visual stimuli in time. Two further experiments examined an alternative explanation, that of a left-to-right scanning mechanism, the results of which also suggested a hemisphere explanation. The results of these experiments are discussed in terms of previous research and theories which located a temporal ordering mechanism in the speech hemisphere.