Opposing effects of stimulus-driven and memory-driven attention in visual search

Abstract

A recent study (Jung, Han, & Min, in press) reported that the extent to which attentional control is strained is a critical factor for observing stimulus-driven attentional capture in visual search. Expanding this study, we tested whether memory-driven attentional capture is also dependent on cognitive mechanism underlying visual search tasks. In our experiment, a group of participants performed a dual task, consisting of a working memory and a visual search task (memory-driven attention group), whereas the other performed only a visual search task (stimulus-driven attention group). Each group was further divided into two groups depending on the search task performed. For visual search tasks, we utilized two different search tasks; Landolt-C and orientation feature search tasks. For the former, participants searched for an outlined square with a top- or bottom-gap among left- or right-gap squares. For the latter, participants looked for a right- or left-tilted line among vertical lines. In a half of the total trials, a memory-matching/salient singleton distractor was present. In the remaining trials, no such a memory-matching/singleton distractor was present. As results, attentional capture by the singleton distractor was found under feature search task, p< .01. On the contrary, the task-irrelevant distractor did not capture when participants performed the Landolt-C search, p> .45. The memory-driven group showed a different pattern. A task-irrelevant, memory matching distractor captured attention when participants performed Landolt-C search task, p< .001. However, no memory-driven attentional capture was found under the feature search, p > .72. Our results demonstrate that the nature underlying visual search tasks is an important factor for observing both stimulus-driven and memory-driven attention. However, the specific patterns of the capture were opposite. These findings point to the role of interplay between the extent to which attentional control is strained and working memory in attentional capture.