Eye movements in response to real and apparent motions of acoustic targets.

Monitoring of eye movements resulting from the tracking of sound displacements in total darkness confirmed the generally accepted idea that smooth pursuit cannot be induced in the absence of a real visible target. Exclusively saccadic movements were obtained with real and apparent displacements of a constant frequency source and with frequency variations associated to spatially calibrated positions through training for 5 Ss. Smooth pursuit eye movements were only observed if S was allowed to point and follow with his hand the perceived position of acoustic targets.