Deja Vu

Hanna Kissinger

What is deja vu?

Deja vu is a french word that actually means, "already seen". It is the phenomenon of having the strong sensation that an experience is happening, has already happened. I chose this topic because I often feel myself feeling deja vu and I'm always curious as to why I get this. My research will help others understand more of what deja vu is.

The Brain and Deja Vu

The reason why Deja Vu happens is because there is a split-second delay in transferring information from one side of the brain to the other. One side of the brain would then get the information twice, once directly, and once from the "in charge" side. So the person would sense that the event had happened before. Scientists aren't exactly sure which parts of the brain are being used, so they have done many different experiments on parts they think it might effect, like the hippocampus and amygdala.

Research and Experiments

Researchers have noticed disturbances of the medial temporal lobe as the cause behind deja vu. Studies of epileptic patients investigated from intracerebral electrodes demonstrate that stimulation of the rhinal cortex can actually induce a deja vu episode.

A study published in the March analyzed the patterns of electroencephalography, signals from the rhinal cortices, hippocampus , and amygdala in epileptic patients for whom deja vu could be induced by electrical stimulation.

The researchers found that synchronized nerual firing between the rhinal cortices and the hippocampus or amygdala were increased in stimulations that caused deja vu. That suggested that some sort of coincident occurrence in medial temporal lobe structures may trigger activation of the recollection system.

However after all this research, it is still a mystery on how exactly we get deja vu.


  • The youngest age reported of deja vu is 5.
  • There are 21 different kinds of deja vu.
  • 70% of people say that they have experienced deja vu
  • Some people experience deja vu about a conversation or dream.