Hemispheric asymmetry for trajectory perception.

Broadly, the right hemisphere is known to be specialized for spatial processing whereas the left hemisphere is known to be specialized for temporal processing. However, it remains unclear how both hemispheres interact when processing spatio-temporal information. This study investigates, from a behavioral point of view, whether spatio-temporal processing involved in trajectory perception generates hemispheric asymmetries. An experimental task requiring the prediction of coincidence between ballistic trajectories and a stationary target was used. Reaction times were analyzed according to various interhemispheric conditions determined by the visual hemifield on which the stimulus was presented and the hand of response. There was shorter reaction time for the left hand than the right hand, and shorter reaction times for the left visual hemifield than the right visual hemifield for both hands. From these findings, it is inferred that there is likely to be right hemisphere specialization for trajectory perception and that this hemispheric asymmetry is independent of handedness.