Prism adaptation: The "target-pointing effect" as a function of exposure trials

Abstract

The amount by which target pointing enhances prism adaptation (the "target-pointing effect") was examined as a function of exposure trials. Each S served in three conditions-target-pointing, no-target, and control-wearing 20-diopter prism goggles in the first two. The S was measured prior to the exposure period on target-pointing accuracy with normal vision but with no visual feedback regarding his performance. Similar measures were taken after the 5th, 10th, 15th, 25th, 35th, 55th, and 95th exposure trials and after each of two consecutive 5-min postexposure periods in the dark. The two experimental conditions led to sharply rising and negatively accelerated adaptation ("negative aftereffect") curves, the asymptotes of which differed markedly, in favor of the target-pointing condition. This difference in asymptotes indicates that the target-pointing effect is not limited to the early portion of the exposure period but, instead, is a relatively permanent phenomenon. There was no decline in adaptation during the postexposure period. © 1971 Psychonomic Society, Inc.