Date of Award


Degree Type


Degree Name

Doctor of Philosophy


This thesis presents a systematic examination of a common visuomotor behavior--locomotion directed to a target in the immediate environment.;The first part of the thesis focuses on an attempt to replicate an earlier finding of a highly accurate transitory short-term memory for target locations (Thomson, 1980, 1983). No evidence of such an accurate short-term memory was found here. The distance to the target, not the elapsed time, affected accuracy of walks with eyes closed. Delays of 2 and 4 s between viewing the target and walking did not result in a deterioration of performance. A 30 s delay did result in less accurate performance, however. Thus, a slowly decaying short-term memory was demonstrated.;The second part of the thesis examined the role of visual context in the control of locomotor accuracy. Being able to see the target led to highly accurate locomotion. Performance was less accurate when subjects had feedback of the area surrounding the target, but not of the target itself. Performance was less accurate still when subjects walked with eyes closed and least accurate when they walked in the direction opposite to the target. Target distance related to locomotor accuracy in a systematic way. Namely, as target distance increased so did locomotor errors.;The next part of the thesis compares peformance on the target-directed locomotion task to performance on a second task in which subjects were asked simply to estimate the distance to the target, and to performance on standard written tests of spatial ability. Performance on the perceptual and locomotor tasks was related. Spatial ability related to perceptual performance, but not to locomotor performance. The last part of the thesis examines individual differences in locomotor accuracy. Males were more accurate than females when asked to walk to a nearby target with their eyes closed.;While the present thesis has only begun to examine all the perceptual processes, motor skills, and cognitive abilities involved in the control of target-directed locomotion, it is clear from the findings reported here that control of this apparently simple behavior is quite complex.



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