Remembering to forget: the amnesic effect of daydreaming.

Daydreaming mentally transports people to another place or time. Many daydreams are similar in content to the thoughts that people generate when they intentionally try to forget. Thus, thoughts like those generated during daydreaming can cause forgetting of previously encoded events. We conducted two experiments to test the hypothesis that daydreams that are more different from the current moment (e.g., in distance, time, or circumstance) will result in more forgetting than daydreams that are less different from the current moment, because they result in a greater contextual shift. Daydreaming was simulated in the laboratory via instructions to engage in a diversionary thought. Participants learned a list of words, were asked to think about autobiographical memories, and then learned a second list of words. They tended to forget more words from the first list when they thought about their parents' home than when they thought about their current home (Experiment 1). They also tended to forget more when they thought about an international vacation than when they thought about a domestic vacation (Experiment 2). These results support a context-change account of the amnesic effects of daydreaming.