False memories for ending of events.

Abstract

Memories are not perfect recordings of the past and can be subject to systematic biases. Memory distortions are often caused by our experience of what typically happens in a given situation. However, it is unclear whether memory for events is biased by the knowledge that events usually have a predictable structure (a beginning, middle, and an end). Using video clips of everyday situations, we tested how interrupting events at unexpected time points affects memory of how those events ended. In four free recall experiments (1, 2, 4, and 5), we found that interrupting clips just before a salient piece of action was completed, resulted in the false recall of details about how the clip might have ended. We refer to this as "event extension." On the other hand, interrupting clips just after one scene had ended and a new scene started, resulted in omissions of details about the true ending of the clip (Experiments 4 and 5). We found that these effects were present, albeit attenuated, when testing memory shortly after watching the video clips compared to a week later (Experiments 5a and 5b). The event extension effect was not present when memory was tested with a recognition paradigm (Experiment 3). Overall, we conclude that when people watch videos that violate their expectations of typical event structure, they show a bias to later recall the videos as if they had ended at a predictable event boundary, exhibiting event extension or the omission of details depending on where the original video was interrupted. Public Significance StatementOur memory for events is fallible: We often forget or distort certain details or even remember things that never actually happened. Here, we showed that participants often inaccurately remember how events ended if the events were interrupted unexpectedly. For instance, if a video clip of a cyclist preparing to ride a bike was interrupted before the cyclist left, people would often falsely remember that they saw the person riding their bike away at the end. Conversely, if the video clip continued to briefly show the cyclist arriving at their destination before the clip was finished, participants would often not recall this additional detail and remember that the clip ended with the person preparing to ride their bike. These experiments highlight how people are biased to recall events as having well-defined endpoints, even when that conflicts with what was actually experienced.