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What is Deja Vu and why does it happen?

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Anekka Scott-Gray

on 24 October 2013

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Transcript of What is Deja Vu and why does it happen?

What is Deja Vu and Why Does it Happen?
History of Deja Vu
In the 19th century, many people came up with hypotheses to explain this phenomenon. Some terms that were used to describe the feeling of deja vu were "been-here-before feeling" and "paramnesia."
Morton Leeds
In the 1940s, Morton Leeds kept a detailed diary of his experiences of deja v, which were frequent. Over the course of 12 months, Leeds had written down 144 diary entries. He had one almost every two days.
Alan Brown and Elizabeth Marsh
Alan Brown, who teaches at Southern Methodist University, and Elizabeth Marsh, who teaches at Duke University, decided to collaborate. Each professor showed his or her other students pictures of locations at the other professor's campus and asked the students to locate certain markers on the background. Three weeks later, the students are shown more pictures, some they have seen before and 89% of the students felt like they visited the other campus. Around half of the students felt deja vu.
There is no simple explanation as to why deja vu occurs but while technology advances, researchers can get a better understanding of memory and how the brain works.
Deja vu is a French term meaning "already seen." The term has been around since French philosopher and researcher Emile Boirac came up with it in 1876.
What is Deja Vu?
Have you ever experienced a sudden feeling of familiarity? Or that something you are experiencing has already happened? That is known as deja vu. It is "any subjectively inappropriate impression of familiarity of a present experience with an undefined past" (Foer 1).
About 60-80% of people have reported experiencing this and it comes randomly and lasts no more than 10 to 30 seconds.
Deja vu was mostly overlooked until the 1980s. It was hard to observe the behaviors of it so psychologists gradually lost interest. Most articles about deja vu were published in journals of parapsychology, a part of psychology that deals with psychic phenomenon, telepathy and more.
He analyzed his records and concluded that his deja vu usually occurred in mundane settings. They also occurred later in the day and week, during periods of stress and fatigue.
Leeds theory is that "the more educated, well traveled, wealthy, and liberal a person is, the more likely he or she is to experience deja vu" (Foer 2).
Their theory is called the "double perception" theory, which says that people sometimes see things twice in quick succession: the first time superficially or peripherally, and the second time with full awareness making the subject look familiar.
Glitches in the Matrix
Epileptic patients consistently experience deja vu when the seizures begin in the medial temporal lobe. These seizures are evoked by alterations in electrical activity in neurons in regions of the brain.
The electrical disturbance is this neural system generates an aura of deja vu prior to the event of the seizure.
This leads to the belief that deja vu is caused by a dysfunctional electrical discharge in the brain.
Mismatches and Short Circuits
Another theory is that deja vu occurs due to a mismatch in the sensory input and memory-recalling output. (Something feeling familar but not a fully recalled memory).
Another theory is that the rhinal neural system, the detection of familiarity, occurs without activation of the recollection system within the hippocampus.
Memory Systems
Some researchers believe that deja vu is a memory-based experience and that the memory centres of the brain are responsible for it.
Certain regions of the medial temporal lobes are important in the detection of familiarity instead of the detailed recollection of specific events.
Works Cited
Reichelt, Amy. "RealClearScience - Why Does Deja Vu Happen?" RealClearScience - Why Does Deja Vu Happen? N.p., n.d. Web. 23 Oct. 2013.
Stanton, Dawn. "Probing Question: What Causes Deja Vu?" Probing Question: What Causes Deja Vu? N.p., 12 Feb. 2010. Web. 23 Oct. 2013.
Foer, Joshua. "The Psychology of Deja Vu." What really happens when moments in our lives seem to repeat themselves? N.p, 9 Sept. 2005.
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