Effects of social stimuli on covert attentional orienting and saccaddic eye-movements during visual search
56.4099, Tuesday, 19-May, 2:45 pm - 6:45 pm, Pavilion
Marcus Morrisey1, M.D. Rutherford1; 1Psychology, Neuroscience & Behaviour, McMaster University
Although visual attention and saccadic eye movements are tightly linked, our attention can move to objects in visual space without a saccade to the object, a phenomenon called covert attentional orienting. Socially significant targets like faces and human bodies attract attention. Using a visual search task we examined reaction to social targets by comparing the relationship between performance measures such as reaction time and error rate and saccadic eye movement measures. Participants briefly viewed a word representing 1 of 6 categories. One image from each category then appeared in a circular array on the screen. Participants identified the image in a target frame (the green frame) as either matching or not matching the presented word. On half of the trials, a distracter frame (the red frame) was also present. Consistent with previous results, participants responded faster when seeking a social target (face or body) compared to non-social targets and this effect was not diminished by inversion. They were slower and more error prone on trials containing a distracter frame. Participants saccadeed first and more often to social targets than to non-social targets but spent less time focused on social targets. When images were inverted, participants did not saccade more often to social stimuli than non-social distracters. Participants varied widely on the proportion of trials in which they saccaded to any object, between 2% and 97%,suggesting that some participants are capable of performing this task peripherally. Indeed, a lower proportion of trials with saccades to targets was associated with faster RT. The evidence supported an attentional effect of social stimuli that is independent of saccadic eye movement in addition to modulation of looking behavior.