Distinctive items are salient during encoding: Delayed judgements of learning predict the isolation effect

Abstract

Three experiments examined the role of salience in predicting superior memory for incongruent or odd items (the isolation effect). We tested the hypothesis that encoding salience emerges over the course of the encoding episode and predicts the isolation effect. In Experiment 1 participants studied lists of unrelated items and lists of categorized items containing an isolated item (from a different semantic category) that was presented either early or late in the list. Participants made delayed judgements of learning (JOLs) for studied items and were then given a free recall test. Results showed that participants had superior recall for the isolated items regardless of their list position and that delayed JOLs predicted this effect for both early and late isolation conditions. Experiment 2 replicated this delayed JOL effect using a different isolation paradigm that used only a single study list. Experiment 3 examined the specific mechanism by which isolated items become salient over the course of encoding and demonstrated that isolated items become salient as knowledge of the list structure unfolds. Results from these studies suggest that isolated items become salient over the course of the study episode, and that this salience predicts the isolation effect in memory.