Attentional deployment during visual search predicts subsequent long-term memory of real world objects

Prior research suggests that repetition-related learning effects during repeated target visual search are sustained after delays (Servant, Cassey, Woodman & Logan, 2018). However, the extent to which participants subsequently remember repeatedly encountered targets is currently unclear. Moreover, little is known about whether EEG activity accompanying repeated encoding processes predict subsequent memory for those objects. We recorded EEG in response to a lateralized target cue while participants (N=20) searched six times consecutively for one of 198 unique real world target objects. Following the search task, we tested their recognition memory for those targets by asking them to select the object they had seen before in an array of 9 objects. We replicate the following findings related to the repetition of targets: 1) reduced reaction time and increased accuracy of visual search; 2) reduced working memory representation of targets indexed by smaller CDA amplitudes; 3) enhanced attentional deployment to targets indexed by larger N2pc amplitudes, and; 4) greater familiarity for targets indexed by reduced FN400 amplitudes. Despite robust repetition-related effects suggestive of learning, nearly 40% of targets were subsequently forgotten. The following behavioral and neurophysiological measures during encoding predicted subsequent memory for a given object: 1) faster and more accurate responses during visual search; 2) greater N2pc amplitude after the first repetition, and; 3) reduced FN400 amplitude after the first repetition. We did not observe a reliable effect due to subsequent memory on CDA amplitudes. These results suggest the likelihood of a target being remembered corresponds with the deployment of visual attention and the degree of familiarity it generates, but not working memory resources. In sum, repetition effects overlap with processes that facilitate successful encoding and recognition of images. Future research should clarify what role repetition-related working memory disengagement serves in encoding of images.