Abstract
New and unannounced color singletons have been shown to capture attention and induce surprise during visual search; a phenomenon referred to as ‘surprise capture’ (Horstmann, 2005). Interestingly, it has been reported that the temporal profile of capture by new and unannounced stimuli is distinct from that of capture by expected stimuli (Horstmann, 2002; 2005; 2006). Specifically, it has been argued that attention shifts to unexpected stimuli are delayed relative to expected stimuli. This claim is interesting because it points to separate underlying attentional control mechanisms for expected and unexpected stimuli. However, much of the work investigating capture by the unexpected has done so using behavioral measures such as response time and response accuracy; measures that can be affected by decision and response level processes that are often unrelated to search. Here we used eye-movements as the primary index of attentional selection to explore the temporal profile of surprise capture and to investigate the claim that shifts of attention to unexpected stimuli are delayed relative to expected stimuli. Across two experiments we found little evidence to support the claim that shifts of attention are delayed to unexpected stimuli during visual search. Rather, the temporal profile of surprise capture appears to reflect delays that manifest post attentional selection that are likely associated with decision and response level processes.
Meeting abstract presented at VSS 2015