Found and missed: Failing to recognize a search target despite moving it

We present results from five search experiments using a novel ‘unpacking’ paradigm in which participants use a mouse to sort through random heaps of distractors to locate the target. We report that during this task participants often fail to recognize the target despite moving it, and despite having looked at the item. Additionally, the missed target item appears to have been processed as evidenced by post-error slowing of individual moves within a trial. The rate of this ‘unpacking error’ was minimally affected by set size and dual task manipulations, but was strongly influenced by perceptual difficulty and perceptual load. We suggest that the error occurs because of a dissociation between perception for action and perception for identification, providing further evidence that these processes may operate relatively independently even in naturalistic contexts, and even in settings like search where they should be expected to act in close coordination.

► A novel manually-assisted search paradigm is introduced – the ‘Unpacking’ task.
► Participants often physically discard the target during search, not recognizing it.
► The error rate is influenced by perceptual factors, but not by cognitive load.
► Post-error slowing in individual moves indicates error awareness.
► The error is argued to result from a decoupling of action and identification systems.