For some people, old dreams can feel like real memories and this experience is referred to as ‘dream-reality confusion’. In two studies by researchers from Maastricht University in the Netherlands, difficulty distinguishing dreaming and reality was reported by a substantial minority of participants (12 per cent in one study and 26 per cent in another).


It has been proposed by other teams of researchers that the experience is particularly common in certain participants (such as those with narcolepsy or borderline personality disorder).

Although there is relatively little research in this area, there are many hypotheses as to why this might occur. One possibility is that the dreams that are confused with reality are different from other dreams (they could be more vivid, for example).

It is also possible that when dream-reality confusion occurs, this could represent unusual memory encoding during sleep (essentially, there is something unusual about the way in which the dream is converted during sleep, before it is stored in long-term memory).

So, how can you tell if you’ve experienced dream-reality confusion? Simply reading this article could help: becoming aware that false memories can develop could have an impact. As one 2021 study found, merely explaining to participants that their recollections could have been based on something other than reality was enough to correct a false memory – while not affecting their ability to remember true events.

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Of course, you can also play detective and consider the evidence. If you think that you swam in Lake Constance with a friend but wonder whether it was in fact a dream, you might want to check whether your friend remembers the experience or whether there are any photos or diary entries from the time to confirm that your fun day at the lake really happened.

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Asked by: Sam Coney, St Helens


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Alice is a Professor of Psychology at Goldsmiths. She has contributed to several diverse research areas, including the longitudinal associations between sleep and psychopathology, behavioural genetics, sleep paralysis and exploding head syndrome. In addition to her scientific contributions she also excels in the public engagement of science. She has published two popular science book (Nodding Off, Bloomsbury, 2018 and Sleepy Pebble, Nobrow, 2019). She regularly contributes articles to the media and has had her work published in outlets including the Guardian, GQ UK, Sud Ouest, Slate Fr, Independent.