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Deja Who?: The Psychology Behind Deja Vu

Adele is releasing an album, Taylor Swift released All Too Well again, Katy Perry just performed riding a giant snail, anyone else getting Deja Vu?

Deja Vu itself is defined as “feeling that a new event has already been experienced or that the same scene has been witnessed before.” Sound familiar? If you have felt this, you are not alone. In fact, 60-70% of people get deja vu at least once in their lifetime. So what is actually going on?

Deja vu remains somewhat a mystery, but neuroscientists have figured out a lot of how this mechanism works. As neuroscientist Dr. Akira O’Connor explains, “Déjà vu is basically a conflict between the sensation of familiarity and the awareness that the familiarity is incorrect.” In other words, we feel like we can recognize an event but don’t know how or why, which makes us feel like our brains are tricking us.

Contrary to popular belief, deja vu isn’t simply a memory error, which is why we shouldn’t worry when it happens. Actually, deja vu occurs when the frontal regions of the brain are trying to correct an incorrect memory. It is our brains “fact-checking” ourselves so we don’t misremember events, and actually is a sign that our brain is working healthily. In fact, this is why deja vu is seen more in young people. Young people tend to get deja vu more often because our excitatory brains are growing and developing and need to fact-check themselves more often.

Deja vu has also been linked to recognition memory. As neuroscientist Anne M. Cleary found, there are lots of similarities between the two. Recognition memory is defined as memory that “allows us to realize that what we are currently experiencing has already happened before,” like recognizing a song on the radio or our next-door neighbor.

This recognition memory is broken down into two parts: recollection and familiarity-based memory. Recollection-based recognition is being able to know exactly when a situation has occurred, like hearing a song and realizing you heard it at a party a month ago. Deja vu is an example of familiarity-based recognition memory, where we know we recognize a memory but we aren’t sure why we recognize it.

So to study this, Cleary designed a study where participants were given a list of celebrity names. Later, they were shown pictures of celebrities, some of which corresponded to the list, some of which did not, and they had to say if they had seen those celebrities previously. So, for example, they might have seen Katy Perry in the first part of the study. And they found that a lot of participants could not, for example, identify that they recognize Katy Perry later but knew they somehow had seen her before. In other words, they were familiar with Katy Perry but didn’t know how.

Cleary also found that Deja Vu can happen when there are simply just parallels between the situation we are experiencing and past ones. So listening to Taylor Swift’s “All Too Well” again in our mom's car when we are 22 can easily trigger deja vu if we listened to it when we were 13 years old in our mom’s car.

But some people are more prone to deja vu than others. Why does this happen? One reason is how tired/stressed we are. In fact, when our brains are really tired, our neuronal systems aren’t as regulated and may be off, resulting in deja vu. At the same time, there are some people that are prone to extreme deja vu, and these reasons can be a little more random. One man in Finland took a mixture of flu medication, which excites certain dopamine neurons, and this caused the man’s persistent deja vu. And in even more rare cases, a plethora of deja vu can be a sign of an epileptic seizure. But not to worry, most of the time deja vu is our brains checking up on our memories, giving us that eerie sense of familiarity.


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