Abstract
Suddenly appearing items (onsets) can attract attention and the gaze even when they are completely irrelevant to the task (onset capture). It has been proposed that onsets modulate affect attention at a very early stage of visual processing, when feature-based information is not (yet) available. Hence, feature-based attention can modulate onset capture only at a late stage of visual processing, via a feedback loop. The present study examined oculomotor capture by differently colored onsets, when the color of the onset either matched or mismatched the expected target color. In line with the view that feature-based attention cannot modulate onset capture, the first results showed high levels of oculomotor capture for a non-matching blue onset as well as a target-matching red onset. However, a control condition revealed that high levels of oculomotor capture by the non-matching blue onset were due to a color aftereffect: When the target changes color from red to grey, it initially appears in a vivid blue that slowly fades to grey. Once the color aftereffect is eliminated (by defining the target as a change from grey to red), the blue onset ceased to capture and only the target-matching red onset captured the gaze. A follow-up study showed that feature-based expectations also modulate onset capture on a trial-by-trial basis, when observers are informed of the target color on the next trial by a word-cue (red or green). Taken together, these results show that feature-based expectations modulate onset capture in a feed-forward manner. Target colors that appear only phenomenally and transiently (e.g., as a result of a color aftereffects), are moreover implemented into feature-based attentional control settings and increase capture for onsets that match the phenomenal target color.
Meeting abstract presented at VSS 2015