Searching for luminance-defined objects through moving apertures(Summary of Awarded Presentation at the 23rd Annual Meeting)

In Experiment 1 the observers searched for a bright, static square arnong three dark squares, The search display consisted of ten frames and was covered with dynamic grayscale noise which had a random or unidircctional motion. The aperture was present during different percentages of noises. By measuring d', it was revealed that detection was more sensitive in unidirectional, rather than randorn, noise, This result suggested that temporal luminance summation played a rniner role in detection. In Experiment 2 thc observers searched for a bright, vertical bar among threc dark vertical bars in the presence of dynamic noisc which was perpendicular, para]leL or random, to the bar orientation. Detection was most sensitive when the movement of the noise was perpendicular. The result suggested that successive visual transients which were visible through the apertures, and which were unrelated to rnovement of the noise, were critical for target detection,