Abstract
We examined how each of exogenous and endogenous attention affects perceived stimulus onset detection. Our preliminary study showed that perceived duration for a visual stimulus would be affected by exogenous attention, but not by endogenous attention (Katsumata & Ichikawa, APCV2019). In the present study, we combined target search task with temporal order judgment task in which we manipulated the spatial attention by pre-cuing method. We presented a white square as a target (1.0 x 1.0 arc deg) at 6 arc deg right or left of the center of screen. Exogenous attention was directed 100 ms before the onset of a target by presenting a cue in increasing luminance of a circular place holder (4.25 arc deg in diameter) from 22.9 cd/m2 to 90.0 cd/m2 while endogenous attention was directed 400 ms before the target onset by presenting a square or diamond place holder. We prepared the valid, invalid, and neutral conditions for the cuing. In each trial for both of exogenous and endogenous attentions, a cross (1.0 x 1.0 arc deg) was presented before or after the onset of the target at 1 arc deg above of the center of screen. SOA between the cross and target ranged from -94ms to 94 ms. Participants were asked to respond to the target stimulus as soon as possible, and then, judged which of target or cross appeared first. We found that the target detection in the valid condition was faster than those in the invalid and neutral conditions for both exogenous and endogenous attentions, and that exogenous attention prolonged the perceived duration although endogenous attention did not. These results indicate that effects of exogenous attention on duration perception would differ from those of endogenous attention. Bases of effects of exogenous and endogenous attentions on duration perception will be discussed.