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

1,956,195 views ・ 2020-09-08

TED-Ed


Please double-click on the English subtitles below to play the video.

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In a study in the 1990s,
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participants recalled getting lost in a shopping mall as children.
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Some shared these memories in vivid detail—
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one even remembered that the old man who rescued him
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was wearing a flannel shirt.
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But none of these people had actually gotten lost in a mall.
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They produced these false memories
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when the psychologists conducting the study told them they’d gotten lost,
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and although they might not remember the incident,
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their parents had confirmed it.
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And it wasn’t just one or two people who thought they remembered getting lost—
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a quarter of the participants did.
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These findings may sound unbelievable,
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but they actually reflect a very common experience.
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Our memories are sometimes unreliable.
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And though we still don’t know precisely what causes this fallibility
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on a neurological level,
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research has highlighted some of the most common ways our memories
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diverge from what actually happened.
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The mall study highlights how we can incorporate information
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from outside sources,
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like other people or the news,
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into our personal recollections without realizing it.
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This kind of suggestibility is just one influence on our memories.
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Take another study,
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in which researchers briefly showed a random collection of photographs
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to a group of participants,
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including images of a university campus none of them had ever visited.
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When shown the images three weeks later,
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a majority of participants said that they had probably or definitely
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visited the campus in the past.
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The participants misattributed information from one context— an image they’d seen—
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onto another— a memory of something they believed they actually experienced.
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In another experiment, people were shown an image of a magnifying glass,
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and then told to imagine a lollipop.
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They frequently recalled that they saw the magnifying glass and the lollipop.
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They struggled to link the objects to the correct context—
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whether they actually saw them, or simply imagined them.
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Another study, where a psychologist questioned over 2,000 people
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on their views about the legalization of marijuana,
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highlights yet another kind of influence on memory.
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Participants answered questions in 1973 and 1982.
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Those who said they had supported marijuana legalization in 1973,
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but reported they were against it in 1982,
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were more likely to recall that they were actually against legalization in 1973—
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bringing their old views in line with their current ones.
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Our current opinions, feelings, and experiences
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can bias our memories of how we felt in the past.
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In another study,
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researchers gave two groups of participants background information
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on a historical war and asked them to rate the likelihood that each side would win.
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They gave each group the same information,
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except that they only told one group who had actually won the war—
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the other group didn’t know the real world outcome.
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In theory, both groups’ answers should be similar,
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because the likelihood of each side winning
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isn’t effected by who actually won—
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if there’s a 20% chance of thunderstorms, and a thunderstorm happens,
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the chance of thunderstorms doesn’t retroactively go up to 100%.
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Still, the group that knew how the war ended
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rated the winning side as more likely to win than the group who did not.
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All of these fallibilities of memory can have real-world impacts.
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If police interrogations use leading questions with eye witnesses or suspects,
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suggestibility could result in incorrect identifications or unreliable confessions.
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Even in the absence of leading questions,
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misattribution can lead to inaccurate eyewitness testimony.
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In a courtroom,
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if a judge rules a piece of evidence inadmissible
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and tells jurors to disregard it, they may not be able to do so.
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In a medical setting, if a patient seeks a second opinion
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and the second physician is aware of the first one’s diagnosis,
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that knowledge may bias their conclusion.
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Our memories are not ironclad representations of reality,
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but subjective perceptions.
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And there’s not necessarily anything wrong with that—
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the problems arise when we treat memory as fact,
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rather than accepting this fundamental truth
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about the nature of our recollections.
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