Is Organization Decided at Encoding? Differentiating the Effects of Encoding and Retrieval Strategies

There is evidence that temporal order information is both encoded and retrieved automatically as a part of episodic memories. However, the influence of this temporal information on recall is modulated by strategic control processes. It is unclear if these processes operate primarily at encoding, by affecting learning, or at retrieval, by organizing memory search. To address this question, we independently manipulated encoding and retrieval strategies. In this experiment, undergraduate participants studied two word lists. Participants were initially told to focus on either temporal or semantic associations and ignore the other (initial strategy). These instructions were used for encoding and recall of List 1 and encoding of List 2. Before recalling List 2, half of the participants were instructed to switch strategies, while the other half kept the same strategy (test strategy). Temporal contiguity was observed in all conditions, even when participants were instructed to completely ignore temporal associations. The initial strategy had no effect on overall temporal or semantic organization. However, there was an effect of test strategy. A semantic test strategy greatly reduced temporal contiguity and enhanced semantic contiguity. Variations in temporal and semantic contiguity may be primarily due to differences in control processes operating at retrieval rather than encoding.