Abstract
Searching for multiple targets is often less efficient than searching for a single target. However, statistical learning and other higher-order regularities have been found to compress object representations in memory, enabling more efficient storage of information. Here, we tested whether this form of memory compression can facilitate search for multiple targets. Participants searched for one of two targets that were cued on each trial. In an initial training phase, specific pairs of targets always co-occurred with each other. In a subsequent test phase, participants searched for previously associated or unassociated pairs of targets. Participants were faster and more accurate at detecting the target when they searched for a previously associated pair of targets. Thus, statistical learning facilitated search for multiple targets. In a second experiment, we tested whether these effects were due to search guidance or decision-making processes. Participants completed the same task while we recorded their eye movements. Again, participants were faster and more accurate at detecting the target when they searched for a previously associated pair of targets. Participants were also more likely to initially fixate the target and fixated fewer distractors, suggesting that statistical learning facilitated search guidance. However, similar findings were not observed for dwell times on the target or distractors, suggesting that these findings were not due to target identification or distractor rejection processes. In a third experiment, we tested whether these effects generalized to other higher-order regularities. Participants completed a similar task in which they searched for semantically related or unrelated pairs of targets. Participants were faster and more accurate at detecting the target when they searched for a semantically related pair of targets. Thus, these effects generalized to semantic relationships. Together, these findings suggest that statistical learning and other higher-order regularities can facilitate search for multiple targets by compressing target representations in memory.