Unique sudden onsets capture attention even when observers are in feature-search mode

Abstract

Two sources of attentional capture have been proposed: stimulus-driven (exogenous) and goal-oriented (endogenous). A resolution between these modes of capture has not been straightforward. Even such a clearly exogenous event as the sudden onset of a stimulus can be said to capture attention endogenously if observers operate in singleton-detection mode rather than feature-search mode. In four experiments we show that a unique sudden onset captures attention even when observers are in feature-search mode. The displays were rapid serial visual presentation (RSVP) streams of differently coloured letters with the target letter defined by a specific colour. Distractors were four #s, one of the target colour, surrounding one of the non-target letters. Capture was substantially reduced when the onset of the distractor array was not unique because it was preceded by other sets of four grey # arrays in the RSVP stream. This provides unambiguous evidence that attention can be captured both exogenously and endogenously within a single task.

Transition from feature-search to singleton-detection strategies in visual search: The role of number of target-defining options.

“…When present, the distractor ring was displayed only in the Lag-2 position. This was done to maximize the number of trials in the present within-subject design, and because it is known that Lag 2 is typically the position that shows the greatest attentional capture (Folk, Leber, & Egeth, 2002, 2008; Spalek, Yanko, Poiese, & Lagroix, 2012).…”