page_title: Memory conformity
section_title: Resistance
hierarchical_section_title: Memory conformity / Resistance
caption_attribution_description: English: This image shows a timeline of when pre and post warnings are introduced in an attempt to reduce memory conformity
context_page_description: Memory conformity, also known as social contagion of memory, refers to the phenomenon where memories or information reported by others influences an individual and is incorporated into the individual's memory. Memory conformity is a memory error due to both social influences and cognitive mechanisms. Social contamination of false memory can be exemplified in prominent in situations involving social interactions, such as eyewitness testimony. Research on memory conformity has revealed that such suggestibility and errors with source monitoring has far reaching consequences, with important legal and social implications. Memory conformity is closely related to the Mandela effect which surfaces after one learns misleading information following the experience of an event.
context_section_description: Prewarnings are warnings given to individuals after an event but before social interaction (when misinformation can be introduced). They are meant to guard an individual against potential memory conformity. They can be warnings against the credibility of a witness or any other attempts to encourage the individual to trust internal sources and resist external conformity.  For many lab experiments, prewarnings have consistently been effective in decreasing memory conformity.  However, some prewarnings can work paradoxically to increase memory conformity by overly sensitizing the initial viewer, who then mistakenly incorporates incorrect post-event information into their initial memory.
  Postwarnings are post-event attempts to reduce conformity. The misinformation effect can occur when the memory of an eyewitness is influenced by misinforming him or her after an event. Studies have found that social "postwarnings," like characterizing an individual as having low credibility after the misinformation has been introduced, can reduce the misinformation or memory conformity effect.  The success of postwarnings depends on the motivation of the individual to be accurate and the individual's perceived threat of being unduly influenced. Even in the face of these postwarnings, many individuals still show memory conformity. Earlier research had shown that postwarnings can cause witnesses to overcorrect their memory exclusion and to neglect to report correct memories that were appropriately gained during the time or experience in question.
  In a 2009 experiment, participants were first shown a crime video and then presented with non-witnessed details (details not in the original video) either through a discussion group, by reading a report, or by watching another version of the video. All three groups similarly reported non-witnessed details after the first rendition of the experiment, but when the experiment was later repeated and participants were warned against incorporating details from their post-video groups, all three groups showed a significant decrease in report of non-witnessed details. This postwarning worked to encourage more sensitive source monitoring, which caused a decrease in conformity.
  Researchers have investigated how the timing of postwarnings influenced conformity. Some researchers have found postwarnings to be ineffective at reducing memory conformity when they warned their subjects one week after they were misinformed. A 2002 study, which presented the warning soon after participants were exposed to the false information found postwarnings to have a significant effect on conformity. 
  A more recent study found postwarnings were ineffective at reducing memory conformity, and that warnings at different times after exposure to misinformation did not matter. However, experimenters did not test all of their participants in one session, which means the warnings were given shortly after the initial event was encoded and shortly after the misinformation was presented.
caption: Timetable of prewarnings and postwarnings against memory conformity
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