Briana L. Kennedy, Steven B. Most; The role of distractors' categorical distinctiveness in emotion-induced blindness. Journal of Vision 2013;13(9):1135. doi: 10.1167/13.9.1135.
In emotion-induced blindness (EIB) experiments, participants search for single targets within rapid serial visual presentation streams (Most, et al., 2005). Most targets appear some time after a distractor, which can be emotionally evocative or neutral. Operationally, EIB is defined as the greater target processing impairment following emotional distractors relative to neutral distractors. However, target processing in streams with neutral distractors is also often impaired relative to baseline. One possibility is that neutral distractors impair target processing due to their categorical distinctiveness within the stream (often a neutral picture of a person among pictures of landscapes). If so, can the impact of emotional distractors also be attributed simply to their categorical distinctiveness within the stream? In the present study, participants engaged in an EIB task under conditions that either minimized or maximized the categorical distinctiveness of the distractor. While the distractor was always categorically unique within each stream, such distinctiveness was minimized in a condition where the streams were composed of categorically heterogeneous items, and it was maximized in a condition where the streams were composed of categorically homogeneous items. Heterogeneous streams included pictures of different common objects (e.g., apple, piano, teapot), whereas homogeneous streams included pictures of a uniform object type (e.g., one stream entirely of teapots, one stream entirely of pianos, etc). Results revealed that in trials with neutral distractors, target accuracy was significantly impaired relative to baseline in homogeneous streams but was not significantly different from baseline in heterogeneous streams. In trials with emotionally evocative distractors, target processing was robustly impaired regardless of the distractors' categorical distinctiveness. These findings suggest that neutral distractors impair target processing when they are categorically distinct from other items in the stream, but that emotional distractors impair target processing even when this categorical distinctiveness is minimized.