Why Later Misinformation Can Enter a Memory

After witnessing an event, another person’s account, a news headline or the wording of a question can affect details reported later. This is known as the misinformation effect. It does not simply erase and rerecord a mental video. Rather, the original experience and later information can compete during retrieval, and a person may confuse whether a detail came from seeing, hearing or inferring it.

In a classic 1974 experiment, Loftus and Palmer showed participants films of traffic accidents. Describing the cars as having “hit” or “smashed” into one another changed estimated speeds. A week later, the group exposed to stronger wording was also more likely to report broken glass that had not appeared in the film. The result showed that a question may do more than read memory; it can supply a new interpretive cue.

The classic study does not show that every memory can be rewritten at will. The misinformation effect varies with the strength of the original memory, the plausibility of the misleading detail, the delay between accounts, the test format and whether people are prompted to consider the information’s source. Some differences may also include response bias rather than a change in remembered content. Later research broadly supports an effect of post-event misinformation on accuracy, while the precise mechanisms remain debated.

In practice, confidence does not guarantee that a detail came from the original event. Recording an important event independently and promptly, avoiding the comparison of answers, and distinguishing “I saw this” from “I heard this later” can be more useful than simply trying harder to remember. This is not a reason to distrust every memory. It is a reason to recognise that memory depends on cues and may bring those cues into reconstruction.

https://doi.org/10.1016/S0022-5371(74)80011-3
https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2023.1201674/full