Poster A82, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
The effect of shared distinctiveness on source memory and illusory correlations: An event-related potential study
Michael Weigl1, Hong Hanh Pham1, Axel Mecklinger1, Timm Rosburg1,2; 1Saarland University, 2University Psychiatric Clinics Basel
An illusory correlation (IC) is the erroneous perception that two uncorrelated categories are correlated. The Shared Distinctiveness Approach (SDA) explains ICs with heightened accessibility of distinctive category combinations in episodic memory. However, empirical evidence for this approach is heterogeneous. In the present event-related potential (ERP) study, we exploited the fact that distinctive items elicit a P300 at encoding, which potentially predicts subsequent memory performance, and investigated the behavioral effect of shared distinctiveness on source memory and ICs. Distinctiveness at encoding was created by infrequently presenting words that differed either in color or valence from frequently presented, positive words. Shared distinctive items deviated in both color and valence. We hypothesized that shared distinctiveness would lead to an enhanced P300 subsequent memory effect (SME), better source memory performance, and an overestimation of the frequency of shared distinctive items. Behavioral results indicate the presence of a shared distinctiveness effect in source memory and an overestimation of the frequency of shared distinctive items. Moreover, the P300 was larger for the distinctive color than for the frequent color and predicted subsequent source memory performance. However, the P300 was unexpectedly larger for positive than for negative stimuli, and shared distinctiveness did not further boost the SME. These results indicate that shared distinctiveness indeed leads to better source memory and ICs, supporting the SDA. The behavioral effects, however, were not associated with the expected SMEs, possibly due to the exclusion of high performing participants from the ERP analyses who had too few trials of later forgotten items.
Topic Area: LONG-TERM MEMORY: Episodic