Scientists discover that human memory might be unreliable after just a few seconds

Memories can easily change over time, or be forgotten entirely, but a new study has found that even the most short-term memories can be deeply unreliable.

New research from the University of Amsterdam has found that participants who were tasked with recalling shapes made mistakes after a very short time frame.

According to their findings, “short-term memory illusions” is a very real thing and could prove that human memory is unreliable even a few seconds after events have taken place.

Dr Marte Otten is the first author of the research which was published in the journal Plos One.

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Their study contested previous research which showed that people who were shown rotated or mirror-image letters often claimed that they saw the letter in its correct shape.

The previous study suggested that this was down to human error and participants misidentifying the shape, Otten and her team believe it was down to issues with memory.

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“Even at the shortest term, our memory might not be fully reliable,” Otten wrote. “Particularly when we have strong expectations about how the world should be, when our memory starts fading a little bit – even after one and a half seconds, two seconds, three seconds – then we start filling in based on our expectations.”

Otten went on to say: “We thought that they are more likely to be a memory effect. So you saw it correctly, but as soon as you commit it to memory stuff starts going wrong.”

Three sets of experiments were conducted on 348 participants as part of the new research. In those tests, 37 per cent said they saw a letter in its correct form, when in fact they had been shown a mirrored letter.

According to the team, the findings suggest those errors came as a result of there pre-held knowledge of the alphabet.

The team are now looking to conduct further research and find real-word applications for the idea of “short-term memory illusions” – including focusing on patterns of speech and intonation of sentences.

“The bigger effects when it comes to social expectations might be intonation, [for example] ‘oh, she said that in a really angry and upset voice,’ right? Whereas maybe the intonation wasn’t that, but it’s just coloured quickly in your memory based on your assumptions about how women are,” Otten said.

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