Testing-induced strengthening of semantically related episodic elements of a memory following partial reactivation.

The testing effect is characterized by a direct benefit on memory retention of reactivated and practiced items compared to their restudy. A scarcely explored phenomenon in consolidated episodic memory is how the direct retrieval of an item by retrieval practice can indirectly strengthen non-reactivated items associated by their semantic context. To study the indirect benefits of retrieval practice we designed a 3-day protocol. On Day 1 subjects learned paired-associates belonging to one of 4 semantic categories on a specific context semantically related to the pair. On Day 2, a certain proportion of the pairs from each category were either tested or restudied by a certain percentage (0%, 25%, 50% and 100%). On Day 3 we tested memory retention of every paired-associate. When analyzing accuracy, we found that increasing the proportion of reactivated pairs benefited testing and restudy to a similar degree, with no testing-related advantage in memory accuracy. However, when comparing reaction times, testing significantly reduced response times. Notably, even pairs from the non-reactivated semantic category showed shorter response times than pairs from any restudied category, suggesting an indirect strengthening through shared temporal acquisition context.