On the cost and benefits of restudying: exploring the list strength effect in self-guided learning

Across five experiments we examined whether restudying a self-selected subset of items impairs memory for the remaining non-restudied items, and enhances memory for the restudied items. This question was inspired by research on the list strength effect, in which re-presentation of only a subset of items from a list impairs recall for items presented only once, and enhances memory for items presented twice. We found that following initial encoding of all items, honouring participants' restudy selections did indeed impair recall for the non-restudied items relative to when no items were restudied. Additionally, we found that memory for the subset of restudied items was enhanced relative to when all items were restudied. These findings expand previous research on the LSE to self-regulated learning and provide important new insights on how some learning strategies may in part be detrimental, but also beneficial, to future memory performance.