Misinformation effect

The misinformation effect happens when a person's recall of episodic memories becomes less accurate because of post-event information. For example, in a study published in 1994, subjects were initially shown one of two different series of slides that depicted a college student at the university bookstore, with different objects of the same type changed in some slides. One version of the slides would, for example, show a screwdriver while the other would show a wrench, and the audio narrative accompanying the slides would only refer to the object as a "tool". In the second phase, subjects would read a narrative description of the events in the slides, except this time a specific tool was named, which would be the incorrect tool half the time. Finally, in the third phase, subjects had to list five examples of specific types of objects, such as tools, but were told to only list examples which they had not seen in the slides. Subjects who had read an incorrect narrative were far less likely to list the written object (which they hadn't actually seen) than the control subjects (28% vs. 43%), and were far more likely to incorrectly list the item which they had actually seen (33% vs. 26%).

The misinformation effect is a prime example of retroactive interference, which occurs when information presented later interferes with the ability to retain previously encoded information. Essentially, the new information that a person receives works backward in time to distort memory of the original event. The misinformation effect has been studied since the mid-1970s. Elizabeth Loftus is one of the most influential researchers in the field. It reflects two of the cardinal sins of memory: suggestibility, the influence of others' expectations on our memory; and misattribution, information attributed to an incorrect source. Research on the misinformation effect has uncovered concerns about the permanence and reliability of memory.

Loftus, Miller, and Burns (1978) conducted the original misinformation effect study. Participants were shown a series of slides, one of which featured a car stopping in front of a stop sign. After viewing the slides, participants read a description of what they saw. Some of the participants were given descriptions that contained misinformation, which stated that the car stopped at a yield sign. Following the slides and the reading of the description, participants were tested on what they saw. The results revealed that participants who were exposed to such misinformation were more likely to report seeing a yield sign than participants who were not misinformed.

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