An earlier study from our laboratory provided initial support for the
hypothesis that information facilitating visual guidance persists in t
he absence of retinal stimulation. The present study supports and exte
nds this hypothesis with three experiments in which visually occluded
subjects positioned a point of light at the location of a previously v
iewed target and also walked in the direction of a previously viewed p
ath. In both tasks, performance was possible following occlusion, and
in all cases, performance slowly and significantly decreased with long
er durations of occlusion. This decay in performance was gradual and h
ad a ''half-life'' of greater than 15 sec. Absolute performance was co
rrelated across tasks. The effect of occlusion on absolute error in th
e localization performance was relatively stable within individuals ov
er a 3-week period. The biological utility of guidance information per
sistence is discussed along with implications for space constancy, ill
usions of motion, and problems of disorientation.