A Test of Retrieved Context Theory: Dynamics of Recall after Incidental Encoding

The temporal contiguity effect (TCE) is the tendency for the recall of one event to cue recall of other events originally experienced nearby in time. Retrieved context theory proposes that the TCE results from fundamental properties of episodic memory: binding of events to a drifting context representation during encoding and the reinstatement of those associations during recall. If these processes are automatic, the TCE should not be dependent on any encoding strategy and should, in fact, be present regardless of encoding intentionality. Here, we ask whether this theory is compatible with recent findings that the TCE is dramatically reduced under incidental encoding, even though memory accuracy is only modestly reduced. We begin by attempting to replicate this finding in a new large-scale study with over 5,000 participants in which we manipulated encoding intentionality between participants in both delayed free recall and continual distractor free recall. A small, but reliable, TCE was observed in all conditions, although the effect was dramatically reduced in incidental encoding. In a simulation study, we demonstrated that retrieved context theory can simultaneously account for both overall recall and the strength of the TCE in incidental encoding conditions. Additional analyses revealed that the incidental TCE is not an artifact of theoretically uninteresting factors, such as recency, and is consistent with being generated by the core contextual dynamics of retrieved context theory.