Australasian Mathematical Psychology Conference 2019

Does source memory exist for unrecognized items?

Julian Fox
University of Melbourne
Adam Osth
University of Melbourne

Source memory is memory for the context in which information is presented. Most models of source memory predict that it is not possible to retrieve source information from items that are unrecognized. For example, multinomial processing-tree models (e.g., Batchelder & Riefer, 1990) and the bivariate signal detection model of Hautus et al. (2008) predict that when an item is unrecognized, source retrieval is not performed and a guess response is elicited. Empirically, there have been mixed results regarding the possibility of source discrimination for unrecognized items. Studies that presented recognition and source judgments for the same item in immediate succession (i.e., a non-blocked design) revealed chance-level source accuracy for unrecognized items, while studies that presented an initial block of recognition judgments, followed by a block of source judgments (i.e., a blocked design), revealed slightly above-chance source accuracy for unrecognized items. A potential explanation for the discrepancy is that source discrimination is possible for unrecognized items, but that when a negative recognition judgment is made immediately prior to the source judgment, as is the case in non-blocked designs, participants are dissuaded from attempting effortful source retrieval. The present study assessed source memory for unrecognized items in three conditions: non-blocked, blocked, and ‘reverse blocked’ (where the block of source judgments preceded the recognition block). It was found that accuracy was significantly above chance in the blocked and reverse blocked conditions, but consistently at chance in the non-blocked condition. These results suggest that source discrimination is above chance for unrecognized items, but that blocked designs are needed to elucidate the effect as non-blocked designs lead to source guessing.