Abstract
A number of recent experiments demonstrated the role of subliminal peripheral events in orienting visuospatial attention (see Mulckhuyse & Theeuwes, 2010 for review). In our earlier experiments (Vakhrushev & Utochkin, 2011), we found out that subliminal central cues (briefly presented faint arrows) can also cause shifts of attention towards cued locations yielding slight but significant acceleration of target detection. In that study, we tested effects of valid vs. invalid cues at two SOAs of 200 and 500 ms and found a cue benefit at 500 ms. In the present study, we investigated subliminally-driven orienting more accurately by introducing neutral condition and using four SOAs of 200, 400, 600 and 800 ms. 26 participants performed speeded detection of a target to the right or left from fixation. Targets were preceded by brief warning signals (clearly visible squares around fixation point). Concurrently with the squares, faint (subliminal) arrow cues appeared at fixation. Cues could be valid (70% target trials), invalid (15%), or neutral (no arrow, 15%). Catch trials (20% of total number) were introduced to control anticipatory responses. Cues subliminality was controlled by postexperimental arrow discrimination test that yielded performance below chance. In the result, it was found no cue effects at 200-ms SOA and significant advantage of valid over invalid condition at 400-ms SOA that is consistent with our earlier results (Vakhrushev & Utochkin, 2011). At 600-ms SOA, we found advantage of both valid and invalid conditions over neutral one. The two possible explanations are discussed. First, it may be elicited by nonspecific arousal effect of subliminal stimulation on reaction time. Second, it may reflect late attentional distribution among two potential target locations following earlier focusing at only one cued location at 400 ms. The future experiments will be conducted to distinguish between these two explanations. Finally, there was no cue effect at 800-ms SOA.
Meeting abstract presented at VSS 2012