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How much do you trust your memory?

Eriko Sugimori
Associate Professor, Faculty of Human Sciences, Waseda University

Many would admit to being a little untrustworthy of their memory when it comes to things such as foreign vocabulary, digits of pi, historical dates (semantic memory), or remembering English vocabulary. However, this is not quite the case when it comes to memory of events people have seen, heard, and experienced themselves (episodic memory). Most people probably think, "I experienced it myself, so I must remember it fairly accurately." In reality, however, episodic memory is far from accurate. Extensive research on eyewitness accounts shows that there is no correlation between eyewitnesses’ certainty about a memory and its accuracy. In other words, whether someone asserts, “I definitely saw this person,” or says, “I am not sure this is the right person,” both memories are equally inaccurate.

The mind only accepts what it wants to see and hear

In an experiment conducted by Simons and Levin in 1998, a young person pretending to be lost (let us call him A) asked passers-by (unknowing participants in the experiment) for directions. While the unknowing participants gave A directions, people would pass between them carrying a door so large that they would momentarily lose sight of each other. At this point, one of the door-carriers (we will call him B) would trade places with A. However, nearly half of the participants carried on giving directions even after the switch, without even realizing that A had been replaced. People pay less attention than one might think. Do you remember what your colleagues were wearing today, the color of their ties? When I asked my students at the end of a class to close their eyes and tell me what color shirt I was wearing that day, only one fifth of them answered correctly.

Reference: The Door Study final (YouTube)

Another study conducted by Cohen in 1981 involved an experiment in which a video of a husband celebrating his wife's birthday was shown to two groups. One group was told that the wife was a waitress while the other group was told that she was a librarian. When their memories were tested, the results revealed that participants tended to remember more details that could be easily inferenced from each profession. The “waitress” group remembered that they were eating hamburgers and there was rock music playing in the background. The “librarian” group recalled the wife wearing glasses and that there were many books on the bookshelves. Based on these observations, Cohen concluded that details that conform to stereotypes are easier to remember than those that do not.

Memories are continuously distorted

Loftus, who is known for her research on false memories, demonstrated how people who watched footage of a traffic accident gave varying answers depending on whether or not they were asked how fast the cars were traveling when they “crashed,” or how fast they were traveling when they “came in contact with each other.” Answers varied by roughly 10 km/h. One might think that you would have a more detailed recollection of shocking situations such as traffic accidents and robberies. However, some experiments show that people are unable to recall surrounding details when they witness something shocking such as a weapon used in a robbery. Because of these experiments, eyewitness testimonies were given less credence in court.

It has been revealed that childhood memories are actually inaccurate. For example, in Gerry and Wade's experiment in 2005, subjects were asked by the tester to speak in detail about the day they rode on a hot air balloon as a child. They were also given a fake photo that was made by editing a childhood photo of the subject with their father, and pasting it into a balloon. At first, participants responded that they did not remember any details about the event. This is expected considering the photo was fake and they had not actually experienced the balloon ride. Despite this however, after visiting the test room for a few days, participants started creating memories, saying, “"I think the balloon ride cost 10 dollars," or "My mother waved at me from the ground and took photos."

Differences in memory depending on the individual

While there are some people who have very positive memories of their own experiences, others look back on all experiences negatively. You might remember that A said something unpleasant to you, even though they meant to compliment you. Dudukovic, Marsh and Tversky (2004) demonstrated that if subjects were instructed to relate an actual event in a way that would interest the listener, they not only spoke about positive aspects of the experience, but also looked back on the experience positively. If you keep telling someone about an unpleasant or painful event in an intentionally comic way, your memory of it might gradually become less negative.

There are people who unintentionally lie, confusing fantasy with reality. It would be a shame to dismiss such people as "liars" since these "liars" are often the creative types that enrich our lives by creating new inventions and producing works of art. I hope we can create a more forgiving and tolerant society by forging an understanding of the inaccuracies of our own and other people’s memories.

Eriko Sugimori
Associate Professor, Faculty of Human Sciences, Waseda University

Specialist field: Cognitive psychology
2001: Graduated from the Division of Educational Studies, Faculty of Education, Kyoto University
2003: Master's degree, Graduate School of Education, Kyoto University
2006: Doctorate degree (Ph.D. in Education), Graduate School of Education, Kyoto University
Awards: 2005 JPA Research Award, Japanese Psychological Association
Works: "Misremembering" and Mental Mechanisms (Kyoto University Press)
Academic career: A previous recipient of the Research Fellowship for Young Scientists program and the Postdoctoral Fellowship for Research Abroad program, offered by the Japan Society for the Promotion of Science, Eriko Sugimori was appointed to her current post in April 2015, after time as an assistant professor at the Waseda Institute for Advanced Study.