The attentional effects of single cues and color singletons on visual sensitivity
16.532, Friday, May 10, 5:30 - 8:00 pm, Vista Ballroom
Alex White1, Rasmus Lunau2, Marisa Carrasco1,3; 1Department of Psychology, New York University, 2Department of Psychology, University of Copenhagen, 3Center for Neural Science, New York University
Goal: Objects appearing in the visual periphery can automatically capture attention. Last year (White, Lunau & Carrasco, 2012) we compared the exogenous cueing effects of a single disk and a color singleton (e.g., a red disk among green ones). We found lower contrast thresholds and response times for stimuli adjacent to the single cue's location than at the other side of the screen. In contrast, the singleton did not affect performance. Here we investigated whether this dissociation arose because single cues and color singletons differ in the spatial profile of attention that they evoke. We tested a range of cue-target distances, including the exact location of the cue (rather than just adjacent to it). Methods: Observers discriminated the orientation of a Gabor patch that appeared at one of four isoeccentric locations. The Gabor was preceded (106 ms SOA) by cues, red or green circles. The cues had 16 possible evenly spaced locations isoeccentric with the Gabor. In the single cue condition, one cue appeared alone. In the interleaved singleton cue condition, 16 cue circles appeared simultaneously, but one differed in color from the rest. The cues' colors were isoluminant. Observers were instructed that all the cues were task-irrelevant and uninformative. Results: On single cue trials, accuracy was higher and response times faster for stimuli 0ºÂ–45º of polar angle away from the location of the cue, compared to 180º away. The color singleton also significantly modulated performance, but to a lesser degree, and with a relative benefit only at 0º (the exact location of the singleton). Conclusion: The onsets of both a single object and an irrelevant color singleton can enhance sensory signals at the cued location. However, the effect of the single cue is larger in magnitude and spatial extent than that of the singleton.