PERCEPTUAL LATENCY AND COMPLEX RANDOM-DOT STEREOGRAMS

Naive observers of random-dot stereograms depicting complex surfaces o ften find that they require several tens of seconds before the impress ion of depth emerges. With practice, however, perception times often d ecrease markedly: perceptual learning occurs. Current explanations of these effects were assessed in two experiments. In the first experimen t the perception times of naive observers for random-dot stereograms w hich depicted the same complex shape but contained different ranges of disparity were measured, In the second experiment the minimum times r equired by experienced observers to perceive a given complex shape in stereograms that contained different ranges of disparity were determin ed. Perception times for the naive observers were all very fast (<3 s) and showed no evidence of perceptual learning. There was no effect of disparity range on perception times in either experiment. It was foun d that very large-disparity (80 min are) complex stereograms could be perceived quickly, even by naive observers. It is concluded that the l ong initial latencies previously reported are not due to surface compl exity nor to the range of disparities present. Other factors, such as dot size, dot density, and the correlation of the stereo images, appea r to be important determinants of efficient stereoscopic performance w hen viewing complex random-dot stereograms.