A dynamic approach offers a unified account of recency and primacy in recognition memory: Integrating associative encoding and temporal context

Recognition memory for short lists shows effects of recency and primacy, which are typically explained using different mechanisms. I propose a single account that jointly explains recency and primacy. This account uses the same mechanisms that explain the dynamics of encoding and recognition of associations between items (Cox & Criss, 2020). When two items are presented simultaneously, separate representations of those items are gradually built by sampling perceptual and semantic features (Cox & Shiffrin, 2017). As this is happening, associative features are formed by making conjunctions between item features, and these associative features then end up shared between the originally separate item representations. I propose that this same process operates when items are presented in sequence, except that instead of forming associative features between two items, associative features conjoin features of a single item with those of its temporal context, which consists of features from preceding items (e.g., Howard & Kahana, 2002; Logan, 2020). This model accounts for recognition accuracy and response times across list lengths and serial positions (Nosofsky, Cox, Cao, & Shiffrin, 2014) as well as facilitation when study order is preserved at test (Schwartz et al., 2005). Recency and facilitation occur because the associative features between the test item and the prevailing temporal context are a strong match to the associative features formed at study. Primacy occurs because temporal contexts are stored in memory and they tend to over-represent early items. The same mechanisms that form associations between items within a trial can also explain associations between trials.