Abstract
In our preliminary study, we found that subjects more often failed to detect a second target in the lower visual field than in the upper visual field for multiple rapid serial visual presentations (RSVP) when each stimulus series were presented at both lower and upper visual fields. One may assume that the differences in target detection performance between upper and lower visual fields were mainly caused by their differences of attentional resolution which is higher at the lower visual field than upper visual field. In this study, we examined whether the saliency of stimulus affect the target detection in observing multiple RSVP series. Participants were required to detect two black alphabet targets (1.25 x 1.25 deg) embedded in two simultaneous black numeral RSVP series, which were presented at the 3 deg left or right from the central fixation cross on gray background. Each frame was presented for 100ms which contains 16.7ms interval. We manipulated the lag between the first and second targets (1, 2, or 6 frames), positional congruency for the two targets (congruent, or incongruent), and distractor saliency (low, or high), which was defined by luminance contrast against the background. We found that the frequency of the second target detection failure was high when the second target was embedded within the high saliency distractors while the first target was embedded within the low saliency distractors. However, the frequency of the second target detection failure was not so high when both of the targets were embedded in high saliency distractors. These results suggest that the strength of suppression in terms of distractors for the second target is determined by relative saliency of the distractors before the second target against the saliency of the distractors before the first target, rather than by the absolute saliency of the distractors before the targets.
Meeting abstract presented at VSS 2017