VISUAL-ATTENTION REVEALED BY AN ILLUSION OF MOTION

Attention is a mechanism to select sensory information. It is a modula tory process which normally cannot be observed as overt responses. A n ew psychophysical method using an illusion of motion perception allowe d us to visualize the field of the magnitude of attention and its dyna mic changes. Based on our experiments using this method we suggest tha t (1) both passive (bottom-up) and active (top-down) attention exert t heir effects on the early stages of visual processing, (2) active atte ntion can quickly and briefly be replaced by passive attention induced by an external event, but can be restored in about 400 ms, and (3) at tention is directed to an object, not space, and follows the object as it moves.