Memory conformity, also known as social contagion of memory, is 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 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. It is one of many social influences on memory.
In and out of lab settings
Famous real-world examples In 2003 immediately after the murder of former Swedish foreign minister Anna Lindh, witnesses were put in a room together so they could not leave the scene of the crime until they were interviewed. The witnesses discussed the scene with each other while in the room, contrary to what they were told to do. The specific descriptions the witnesses gave about the perpetrator upon leaving the room were influenced by each other, causing the police to collect false information during the initial search for the perpetrator. The perpetrator, Mijailo Mijailovic, was caught on camera and did not match the descriptions that the eyewitnesses gave. Conclusions have been made that the cause of this false search was rooted in witnesses discussion of their accounts with one another, which caused them to influence each other's memories of the event.
Another example occurred after the 1995 Oklahoma City bombing. Three employees were working at the location where Timothy McVeigh rented the truck he used in the bombing. Two of the witnesses originally thought that McVeigh was by himself, but the third believed that McVeigh came with an accomplice. After the three were left to discuss the event, the two witnesses came to the conclusion that there was indeed a second person who assisted McVeigh. The FBI believes that this "accomplice" never existed. The employee who claimed to have seen an accomplice most likely unintentionally influenced the other two employees, causing them to make later claims about an accomplice as well.
A possible example is an event from 1941 involving Rudolf Hess, Adolf Hitler's Chief of Staff, who had flown to Scotland to present the Duke of Hamilton with a peace proposal between Germany and Britain. Hess parachuted from his aircraft some miles off course, was apprehended and held, until two people who had met him years before, could be brought to identify him as Rudolf Hess. Prior to their meeting with Hess, the two individuals heard a radio report that Rudolf Hess had parachuted into Scotland and had been apprehended. The report colored their confirmation of Hess's identity when the man in question was shown to them. Despite the fact that about a hundred people in London could have positively identified Hess, the identification was made by these two men who anticipated it was Hess they were about to identify due to the report they had heard. Because no other people were ever called to identify Hess in subsequent years, there has been speculation that a double had impersonated Hess in this event.
Laboratory studies
Memory conformity and resulting misinformation can be either encountered socially (discourse between two or more people) or brought about by a non-social source. One study found that if an individual was given false information during a post-event discussion, the accuracy of the individual's memory was lowered, but if the individual was given accurate information during the discussion, then their recall was more accurate. Even when the subject's initial memories were very accurate, individuals who discussed their memory with someone who had witnessed a slightly different scene exhibited a decrease in accuracy due to conformity. Simply hearing another individual's report of an event can be enough to alter one's confidence in one's own recalled memory. Memory conformity has been shown to occur on tasks involving both free recall and recognition, with study participants being more likely to provide inaccurate details of photographs after having discussed them with another participant.
Memory conformity can typically be created in the research setting by using photos or videos which depict crime scenes. Typically, participants are led to believe that they had all viewed the same scene, but in reality the videos and photos were slightly different for each participant, or they were introduced to a confederate, who reported a different memory of the same event. After viewing, the participants are tested on their initial accuracy, and then allowed to discuss their memory with others to see how social interaction affects the accuracy of their memories. An early study found that despite having seen different scenes, 79% of pairs were able to come to an agreed-upon conclusion, meaning that nearly half of the individuals conformed to the other member of his or her pair. It is worth noting that, in this study, 98% of participants were initially accurate in their first recall of the scene.
Underlying mechanisms Three influences can contribute to memory conformity and social contagion errors: normative influences, information influences and source monitoring errors. Normative and informational influences on memory are both social influences that can lead to memory conformity.
Social influences Normative influence, first suggested in the 1955 Asch conformity experiments, states that in social situations, people are more likely to make statements that they do not believe, in order to conform to social norms and to gain social acceptance. For example, research has shown that people who have social interactions after an event are more likely to change their thoughts about the event to something other than what they actually witnessed. In one experiment, 60% of participants reported findings that they could not possibly have witnessed.
A study analyzed which characteristics of dialogue, specifically in regard to response order from participants, had an effect on or predicted memory conformity. The study showed that the first member to report an element of their memory was resistant to influence, even when the memory was disputed by another person. In contrast, the person who was not the first to mention a detail were more likely to be influenced and subsequently report what the other person had seen, even if the memory report differed in detail to what they had themselves seen. Researchers suggested that normative conformity may have influenced the changes in memory reports because individuals wanted to appear to be in agreement with other around them in order to create a smooth interaction and increase their chances of being liked.
Information influence describes a kind of conformity in which people tend to report what someone else has stated previously because they depend on the other person to resolve uncertainty. People are more likely to conform, if they believe that their information source had more time to learn the materials, or had better visual acuity, or expressed high confidence in their judgment. One study found that those considered to be high-power individuals are more likely to influence those deemed to be low-power. High-power people are more likely to express themselves and lead discussions, while lower-power individuals will tend to follow and depend upon the more confident individual.
One study considered the effect on memory conformity when participants had to discuss information was encountered that omitted, added to, or contradicted originally encoded items. This study revealed that people are more likely to be influenced when encountering an additional item or detail in their memory, in comparison to omitted or contradictory manipulations. Researchers speculated that the uncertainty and debate that occurred in trials surrounding the confirmation of additional information supplied by another person convinced them that they had missed particular details, likely due to a lapse in attention, that ultimately led to altering their memory report. With the motivation participants had to be accurate in their reporting, informational influence was suspected to have played a role in the increased conformity that was found in this experiment.
Source monitoring
Source monitoring is the conscious effort one makes to determine the source from which a memory or piece of information came. These sources tend to be one's own experience with others and the world, or their own imagination and dreams. Specific and vivid details within each of these helps determine which of the possibilities is the most probable source. For one’s outer experience, these details usually involve the setting and events that occurred around that time. These are then contrasted with other events that have occurred in the past to judge what the source could have been. Personal, concrete experiences are often more vivid and have more detail than imagined experiences. Noticing the difference between details and vivid details can help to determine whether a piece of information came from experience or the imagination.
Source monitoring has a relationship with the frontal lobe of the brain, which is the region of the brain that is correlated with judgment and decision-making. The hippocampal region of the brain, involved with memory, is activated when retrieving information from external events. After having recalled a memory or piece of information with the help of the hippocampus, the brain uses its judgment abilities within the prefrontal cortex to determine whether it was received by a specific source or another.
Source monitoring errors is another mechanism underlying memory conformity. A source-monitoring error can lead to an incorrect internal attribution of a memory (the belief that a memory was made from first-hand experience), when in reality that information had an external source (someone else relayed the information). When a piece of information or a memory of an event has similar qualities to that of another, it is possible that the information is confused and stored incorrectly, because there are not enough differences to permit a strong enough distinction between the two. This can lead to false attributions when working in relation to sources. For example, when two men were speaking in a previous situation, it may be more difficult to recall which of them presented a specific piece of information when compared to one man and one woman speaking.
Suggestions and the opinions of others can highly affect whether an error in memory or source attribution occurs. Social interactions can increase source-monitoring errors, with law studies showing that participants attributed their memory to an incorrect source about 50% of the time. Real-life events have provided examples in which errors in source monitoring have occurred, especially in relation to criminal cases or terrorist events. To show this, a study was done with an Israeli plane crashing in Amsterdam. After being asked where each person had received the news of the event, many falsely reported their source of the information. Most claimed to have seen it on the television, although the event had not been filmed. It is likely that through descriptions of the event and stories, the brain created the event visually, causing the person to think it was seen on television.
Important variables
Age