Abstract

We describe an experiment in which the discriminability of stimulus orientation was measured over a range between 10° and 90°. The test stimulus was a vertical line segment, which subjects detected in a visual search paradigm. The thirty-five distractors were parallel line segments placed in a jittered hexagonal array. For a given distractor orientation, the detectability (d′) of the test line was measured as a function of display duration. D′ increased approximately linearly with duration over the range tested. The rate of increase depended greatly on distractor orientation. D′ improved gradually when the difference was small and very quickly when the orientation difference was large. Apparently, subjects searched the display at a constant rate which depended on the difference in orientation.

© 1989 Optical Society of America