Picture Encoding suppresses False Memory in the Deese-Roediger-McDermott paradigm through both Distinctiveness Heuristic and Impoverished Relational Encoding

Picture encoding of study lists consistently suppresses false memories in the Deese-Roediger-McDermott paradigm (i.e., DRM paradigm). Traditional studies argue that pictorial suppression is based on retrieval processes such as memory monitoring strategy rather than encoding processes such as impoverished relational processing. Whereas, more recent studies reveal the contribution of encoding processing. We attempted to verify whether these processes actually contribute to the suppressive effect of picture encoding. First, to confirm the difference between picture and word encoding, we measured and compared mean backward associative strength (i.e., BAS) of the lists, which is one of the proxies of relational processing. Results showed that BAS in word lists was higher than picture lists, indicating that relational processing was impoverished in picture encoding. Second, to determine whether the difference in encoding and retrieval processing between picture and word conditions contribute to the false memory suppression, we performed the DRM paradigm manipulating encoding condition (i.e., picture vs. word) as within- (Experiment 2) or between-design (Experiment 3). The results of these experiments demonstrated that the suppressive effect was observed in both designs. Converging with additional analyses across the experiments, the results implicated that both encoding and retrieval processing contribute to pictorial suppression. Thus, we could provide novel evidence of their complementary mechanism in suppression of picture encoding.