Attentional capture by salient distractor in a tactile search task

Previous studies on tactile search have only used one target and homogenous distractors (fillers) (Forster, Tziraki, & Jones, 2015). Therefore, it remains unclear whether a distractor that shares a relevant feature will capture attention in a similar fashion to what has been observed in vision (Gaspar & McDonald, 2014; Hickey, McDonald, & Theeuwes, 2006). We used a task with 4 vibrotactile stimuli with different frequencies on 4 locations (2 fingers of 2 hands). Participants were asked to respond to the elevation of the target (top vs bottom fingers) while ignoring other simultaneous stimuli. There were 4 different conditions: target with three fillers (target only trials), distractor with three fillers (distractor only trials), target and distractor simultaneously the same hand (same side trials) or to the opposite hand (opposite sides trials) and two fillers. Results demonstrated that the distractor captured attention, resulting in slower RTs and lower accuracy on distractor present trials as compared to distractor absent trials. ERP analyses show the presence of the N140cc on target only and same side trials. Interestingly, there was a reliable N140cc also on distractor trials suggesting that the distractor was able to capture attention. In addition, the N140cc was reduced on opposite sides trials as compared to target only trials. This suggests that although participants were able on average to direct attention to the target, the presence of the distractor had detrimental effects on search performance.