The consequences of differentiation in episodic memory: Similarity and the strength based mirror effect

When items on one list receive more encoding than items on another list, the improvement in performance usually manifests as an increase in the hit rate and a decrease in the false alarm rate (FAR). A common account of this strength based mirror effect is that participants adopt a more strict criterion following a strongly than weakly encoded list (e.g., Cary & Reder, 2003; Stretch & Wixted, 1998). Differentiation models offer an alternative: more encoding leads to a more accurate memory representation for the studied item. A more accurate representation is less confusable with an unrelated item, resulting in a decrease in the FAR (McClelland & Chappell, 1998; Shiffrin & Steyvers, 1997). Differentiation models make additional predictions about reversals in FARs for foils similar to a studied item as a function of the composition of the study list. These predictions were empirically tested and confirmed.