Measuring shared knowledge with group false memory.

We conducted two experiments to investigate the effects of word list consistency and group collaboration on false memory. Using the DRM (Deese-Roediger-McDermott) paradigm, the first experiment (n = 121) examined false memory in a group; participants collaborated to select keywords using a between-subject condition of a consistent or randomized word list. The proportion of false responses was larger than that of error responses, especially for the consistent word list condition (p < 0.001), and group collaboration increased false recognition for both word lists (p < 0.001). Using an applied within-subject word list condition, the second experiment (n = 119) confirmed the results of Experiment 1. Furthermore, individual differences Euclidean distance model analysis revealed a difference in the shared cognitive dimension related to group false memory.