This study aimed to analyse the effect of retention intervals on associative and thematic false memories. Two experiments, using two types of critical items that were either associatively or thematically related to studied material, were conducted. In both experiments, one group of participants performed a recognition test immediately after the presentation of lists, and another group performed the task one week later. In Experiment 1, the recognition test consisted of pairs of items with four response alternatives (both items had been presented, only the left item had been presented, only the right item had been presented or none of the items had been presented). Critical items were also manipulated so that they were either presented in or absent from the list. In Experiment 2, a standard recognition test that differed in the mode of presentation was used: self-paced or speeded response. Both experiments showed that associative critical items were more recognised than thematic critical items in the immediate condition. However, whereas associative critical items decayed after a one-week delay, thematic critical items were similarly recognised at both retention intervals. The findings of the present study suggest that each type of process - associative and thematic - behave differently over time.
Keywords: DRM paradigm; False memories; associative activation; retention interval; thematic extraction.