The role of retrieval during study: Evidence of reminding from self-paced study time

Semantic associations restore neural encoding mechanisms

Lapses in attention can negatively impact later memory of an experience. Attention and encoding resources are thought to decline as more experiences are encountered in succession, accounting for the primacy effect in which memory is better for items encountered early compared to late in a study list. However, accessing prior knowledge during study can facilitate subsequent memory, suggesting a potential avenue to counteract this decline. Here, we investigated the extent to which semantic associations-shared meaning between experiences-can counteract declines in encoding resources. Our hypothesis is that semantic associations restore neural encoding mechanisms, which in turn improves memory. We recorded scalp electroencephalography (EEG) while male and female human participants performed a delayed free recall task. Half of the items from late in each study list were semantically associated with an item presented earlier in the list. We find that semantic associations improve memory specifically for late list items and selectively modulate the neural signals engaged during the study of late list items. Relative to other recalled items, late list items that are subsequently semantically clustered-recalled consecutively with their semantic associate-elicit increased high-frequency activity and decreased low-frequency activity, a hallmark of successful encoding. Our findings demonstrate that semantic associations restore neural encoding mechanisms and improve later memory. More broadly, these findings suggest that prior knowledge modulates the orientation of attention to influence encoding mechanisms.

Personal reminders: Self-generated reminders boost memory more than normatively related ones

People generate reminders in a variety of ways (e.g. putting items in special places or creating to-do lists) to support their memories. Successful remindings can result in retroactive facilitation of earlier information; in contrast, failures to remind can produce interference between memory for related information. Here, we compared the efficacy of different kinds of reminders, including participant's self-generated reminders, reminders created by prior participants, and normatively associated reminders. Self-generated reminders boosted memory for the earlier target words more than normatively associated reminders in recall tests. Reminders generated by others enhanced memory as much as self-generated reminders when we controlled output order during recall. The results suggest that self-generated reminders boost memory for earlier studied information because they distinctly point towards the target information.