To Seen, or Not to Seen

By Lizzie Landry

Déja Vu

Have you ever had that gut feeling that you've either been somewhere or seen something before? Well, if you're like me, I bet you have. But no worries; lots of people do and I promise you're not crazy.

What Is Déja Vu?

It means Already Seen!

The first thing you need to understand about Deja Vu is memories. Memories come from something that we have experienced in our lives. Memories where we have encountered information is called source memory. The sensation or feeling of deja vu comes as a sort of blast from the past due to the source memory. It's a feeling that you get when you have a compelling sense of familiarity or sense of eeriness.

There are also three different types of Deja Vu:

  • Déja Veçu - already experienced or lived through
  • Déja Senti - already felt
  • Déja Visite - already visited

The Brain

The part of the brain affected by deja vu is the hippocampus; which stores memories. Often, our memories overlap with similar situations and events; so the brain uses a process called pattern separation to differentiate between memories. These overlapping memories or 'misfires' is considered a cause for the sensation of deja vu, as well as the failure of the pattern separation process. Although the research is sparse, deja Vu can also be linked to levels of the neurotransmitter dopamine, which is known as the feel good hormone.

Other parts of the brain that are affected:

  • temporal lobes/amygdala - concerned with the past
  • frontal lobes - concerned with the future
  • underlying, intermediate portions (the limbic system) - concerned with the present

Other Theories

There are unlimited amounts of different theories as to why we experience deja vu, but here are a few of them:

1. Researchers at Colorado State University found that they can cause people to have feelings of deja vu under carefully controlled circumstances. They tested this theory by the use of video games; or specifically The Sims. Their experiments' results suggested that deja vu involves a memory dysfunction. This malfunction is triggered when you see something that is similar to something that you've seen before.

2. Another theory suggests that deja vu is caused by glitches when our brain processes information. Specifically, these glitches occur in the information that passes through perception and memory. This theory is supported by people who suffer from epilepsy.

3. According to psychological and neuropsychological research, deja vu is an anomoly, or something that deviates from what is standard, normal, or expected, of memory. The sense of recollection is at the time stronger than the time o experience.

4. Due to the exploration of vision, it is also believed that one eye records faster than the other. This creates the strong recollection of what is supposedly "already seen".

The Research and Psychologists

Who discovered deja vu?

Emile Boirac was the first person to use the term 'deja vu' in his book "L'Avenir des Sciences Psychiques" . However, he did not research it in depth; and Sigmund Freud is credited with theorizing these experiences. From these ideas, scientists used the theory of paramnesia to explain deja vu for most of the 20th century.


The most famous experiment dealing with deja vu was conducted by psychologist Wilder Penfield in 1955. Within his experiment, he electrically stimulated the temporal lobes, and found that 8% of his subjects experienced some type of memory. He, however, thought he elicited actual memories. Today, it is concluded from his experiment he may have instead elicited hallucinations and the first examples of artificial deja vu.