Misinformation Effect

Memory Bias

The tendency for post-event information to interfere with the memory of the original event.

Example of Misinformation Effect

A witness to a car accident reads a news article that incorrectly states the traffic light was red. Later, they genuinely remember seeing a red light, even though it was actually green. The post-event information from the article has become integrated into the witness's memory of the actual event.
Parents repeatedly tell their child about a family vacation, including details the child was too young to actually remember. As an adult, the person believes they have vivid memories of the trip. The stories heard over the years have created false memories that feel authentic.

Note

Pioneered by Elizabeth Loftus through her extensive research on eyewitness memory starting in the 1970s.

This is a common bias

Misinformation Effect

Extended Explanation

The Misinformation Effect is a cognitive bias in which a person's memory of an event becomes distorted or altered by information encountered after the event occurred. When we are exposed to misleading information following an experience, that new information can become incorporated into our memory, making it difficult or impossible to distinguish what we actually witnessed from what we were told later.

This phenomenon was extensively researched by psychologist Elizabeth Loftus, whose studies demonstrated how easily memories can be manipulated through suggestive questioning or false information. In one famous experiment, participants who were asked about cars "smashing" into each other reported higher speed estimates and were more likely to falsely remember broken glass than those asked about cars "hitting" each other. The choice of words literally altered their memories.

The misinformation effect has profound implications for eyewitness testimony in legal proceedings. Witnesses who are exposed to media coverage, conversations with other witnesses, or suggestive questioning by investigators may develop memories that blend what they actually saw with information they encountered afterward. These false memories feel just as real as genuine ones, making them particularly dangerous in courtroom settings.

Understanding the misinformation effect highlights the fragility of human memory. Our memories are not like video recordings that can be replayed accurately; they are reconstructive processes that can be influenced by subsequent experiences. This knowledge encourages appropriate skepticism about the reliability of memory and the importance of proper interview techniques.