Abstract
When multiple attentional control settings are available, observers often use suboptimal strategies in visual search. We used a variant of the adaptive choice visual search task (Irons & Leber, 2016) to examine the dynamical adaptation of feature search and singleton detection mode, search modes known to be susceptible to suboptimal selection (Bacon & Egeth, 1994). In a visual search task, participants were free to select one of two shape targets in each trial. One of the targets was always colored; the other one was always gray. The amount of colored and gray distractors varied systematically from displays in which either the gray or the color target was a color singleton. These singleton displays were connected by transition phases in which the number of colored and gray distractors predictively changed across trials from displays containing only gray to displays containing only colored distractors. As the target shape was known in advance, we assumed that participants could use feature search to find either target in all trials, whereas they could use singleton detection mode in trials with only few colored or gray items. We examined the proportion of chosen gray and colored targets during the trial sequence. Results showed that participants selected the color and gray target most frequently when it was a singleton, yet target selection was far from optimal. During the transition phase participants were more likely to switch to the target that was a singleton at the end of the transition. The extent to which the participants adapted their target choice to the trial sequence differed among individuals and was correlated with individual working memory capacity. Overall, these findings suggest that observers dynamically switch to singleton detection mode when optimal but that switching between search modes differs among individuals.
Acknowledgement: This research was supported by the Deutsche Forschungsgemeinschaft (German Research Foundation SFB/TRR 135, TP B3 and RTG 2271).