Are all of your memories real? - Daniel L. Schacter

In a study in the 1990s, participants recalled getting lost in a shopping mall as children. Some shared these memories in vivid detail— one even remembered that the old man who rescued him was wearing a flannel shirt. But none of these people had actually gotten lost in a mall. They produced these false memories when the psychologists conducting the study told them they’d gotten lost, and although they might not remember the incident, their parents had confirmed it. And it wasn’t just one or two people who thought they remembered getting lost— a quarter of the participants did.

These findings may sound unbelievable, but they actually reflect a very common experience. Our memories are sometimes unreliable. And though we still don’t know precisely what causes this fallibility on a neurological level, research has highlighted some of the most common ways our memories diverge from what actually happened. The mall study highlights how we can incorporate information from outside sources, like other people or the news, into our personal recollections without realizing it. This kind of suggestibility is just one influence on our memories.

Take another study, in which researchers briefly showed a random collection of photographs to a group of participants, including images of a university campus none of them had ever visited. When shown the images three weeks later, a majority of participants said that they had probably or definitely visited the campus in the past. The participants misattributed information from one context— an image they’d seen— onto another— a memory of something they believed they actually experienced.

In another experiment, people were shown an image of a magnifying glass, and then told to imagine a lollipop. They frequently recalled that they saw the magnifying glass and the lollipop. They struggled to link the objects to the correct context— whether they actually saw them or simply imagined them. Another study, where a psychologist questioned over 2,000 people on their views about the legalization of marijuana, highlights yet another kind of influence on memory.

Participants answered questions in 1973 and 1982. Those who said they had supported marijuana legalization in 1973, but reported they were against it in 1982, were more likely to recall that they were actually against legalization in 1973— bringing their old views in line with their current ones. Our current opinions, feelings, and experiences can bias our memories of how we felt in the past.

In another study, researchers gave two groups of participants background information on a historical war and asked them to rate the likelihood that each side would win. They gave each group the same information, except that they only told one group who had actually won the war— the other group didn’t know the real-world outcome. In theory, both groups' answers should be similar because the likelihood of each side winning isn’t affected by who actually won— if there’s a 20% chance of thunderstorms, and a thunderstorm happens, the chance of thunderstorms doesn’t retroactively go up to 100%.

Still, the group that knew how the war ended rated the winning side as more likely to win than the group who did not. All of these fallibilities of memory can have real-world impacts. If police interrogations use leading questions with eyewitnesses or suspects, suggestibility could result in incorrect identifications or unreliable confessions. Even in the absence of leading questions, misattribution can lead to inaccurate eyewitness testimony.

In a courtroom, if a judge rules a piece of evidence inadmissible and tells jurors to disregard it, they may not be able to do so. In a medical setting, if a patient seeks a second opinion and the second physician is aware of the first one’s diagnosis, that knowledge may bias their conclusion. Our memories are not ironclad representations of reality, but subjective perceptions. And there’s not necessarily anything wrong with that— the problems arise when we treat memory as fact, rather than accepting this fundamental truth about the nature of our recollections.