What Is the Misinformation Effect?

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In a famous experiment by psychologist Elizabeth Loftus, participants were shown video footage of a traffic accident. After watching the clip, the participants were then asked a number of questions about what they had observed, much in the same way police officers, accident investigators, and attorneys might question an eyewitness. One of the questions asked was "How fast were the cars going when they hit each other?

" In some instances, however, a subtle change was made; participants were instead asked how fast the cars were going when they "smashed into" each other.

What the researchers discovered was that simply using the word "smashed" instead of "hit" could change how the participants remembered the accident. A week later, the participants were once again asked a series of questions, including "Did you see broken glass?" Most of the participants correctly answered no, but those who had been asked the "smashed into" version of the question in the initial interview were more likely to incorrectly believe that they had indeed seen broken glass.

How can such a minor change lead to such differing memories of the same video clip? Experts suggest that this is an example of the misinformation effect, a memory phenomenon that can introduce misleading or incorrect information into memory and even contribute to the formation of false memories.

What Is the Misinformation Effect?

The work of Loftus and her colleagues has demonstrated that the questions asked after a person witnesses an event can actually have an influence on the person's memory of that event. Sometimes when a question contains misleading information, it can actually distort the memory of the event, a phenomenon that is known as the misinformation effect.

  Loftus herself has explained, "The misinformation effect refers to the impairment in memory for the past that arises after exposure to misleading information."

Understanding Why the Misinformation Effect Happens

So why exactly does the misinformation effect happen? There are a few different theories:

  • One explanation is that the original information and the misleading information presented after the fact get blended together in memory.
  • Another possibility is that the misleading information actually overwrites the original memory of the event.
  • Researchers have also suggested that since the misleading information is more recent in memory, it tends to be easier to retrieve.
  • In other cases, the pertinent data from the original event may never have been encoded into memory in the first place, so that when misleading information is presented, it is incorporated into the mental narrative to fill in these "gaps" in memory.

Factors That Influence the Misinformation Effect

A number of factors contribute to the misinformation effect and make it more likely that false or misleading information distorts memories of events:

Time: If misleading information is presented some time after the original memory, it is likely to be much more accessible in memory.

This means that the misleading information is much easier to retrieve, effectively blocking the retrieval of the original, correct information.

Discussing the Event with Other Witnesses: Talking to other witnesses following an event can distort the original memory of what really happened. The reports given by other witnesses might conflict with the original memory, and this new information might reshape or distort the witness's original memory of events as they occurred.

News Reports: Reading news stories and watching television reports of an accident or event can also contribute to the misinformation effect.

People often forget the original source of information, which means that they might mistakenly believe that a piece of information was something they observed personally when really it was something they heard in a post-event news report.

Repeated Exposure to Misinformation: The more often people are exposed to misleading information, the more likely they are to incorrectly believe that the misinformation was part of the original event.

More Psychology Definitions: The Psychology Dictionary


Kellogg, R. T. (2012). Fundamentals of cognitive psychology. Thousand Oaks, CA: SAGE Publications.

Loftus, E. F. (2005). Planting misinformation in the human mind: A 30-year investigation of the malleability of memory. Learning and Memory, 12, 361-366.

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