Yifan Fang¹ (), Viola Störmer¹; ¹Dartmouth College

Studies show that when a target stimulus is selected among similar distractors, attention is not tuned to the exact target feature but away from it, in order to increase the signal-to-noise ratio between targets and distractors. To date, most research investigating this “optimal tuning” account of attention have focused on relatively simple visual features, such as color or orientation (Chapman et al. 2023; Navalpakkam & Itti, 2007). In the present study, we investigated whether similar repulsion effects would occur for complex, higher-level visual representations such as faces. Participants (N=32) performed a visual search task in which they were presented with an oddball target face among three distractor faces for 1500ms and were asked to select the location of the target. On each trial, the target was chosen randomly from a circular continuum of emotional faces (ZeeAbrahamsen & Haberman, 2018). The distractors were selected to be either similar (±60°) or dissimilar (±120°) from the target. To test how search context modulates the perception of the target on correct search trials, participants completed a 2-alternative forced choice task reporting which of two faces – the target or the foil – was most similar to the target immediately after each trial. Critically, the foil was offset by 15° or 40°, either away or towards the distractor. If attention is tuned away from similar distractors, participants should choose the foil more often when it is rotated away from the distractor relative to when it is rotated towards the distractor. Our results showed that this was the case for the 40° foil condition (p = 0.01) and to some extent for the 15° foil condition (p=0.13). As predicted, there was no effect when search distractors were dissimilar. Our results suggest that the repulsion effect found for simple features can be generalized to faces.