Almost all of us have experienced what is called deja vu: a strange feeling which says that the new events we are actually feeling we experienced much earlier. This event could be a new place being visited, the conversation being carried out, or a TV show being watched. More strangely, again, we are also often not able to really remember when and how previous experiences that happened in detail. All we know is there is a mysterious sensation that makes us not familiar with the new event.
The strangeness of this phenomenon of deja vu later gave birth to some metaphysical theories that try to explain the cause. One is the theory that deja vu is actually derived from a similar incident had ever experienced by our souls in one of the previous incarnation of life in the past. How to explain his own psychology?
Age-related and degenerative diseases
Initially, some scientists think that deja vu occurs when the optical sensation received by the eye to the brain (and perceived) ahead of the same sensation received by the other eye, causing a familiar feeling on something that actually the first time views. Theory known by the name “Optical pathway delay” was broken when in December last year found that blind people can experience deja vu through the senses of smell, hearing, and touch.
In addition, before Chris Moulin of the University of Leeds, UK, have also found patients with chronic deja vu: the people who are often able to explain in detail the events that never happened. They felt no need to watch TV because they felt had been watching the TV show before (though not yet), and they even felt no need to go to the doctor to treat his ‘sick’ because they felt it was going to the doctor and can tell things in detail during his visit ! Instead of misperceptions or delusions, the researchers began to look into the causes of deja vu in the brain and our memory.
Recently, an experiment in mice may provide new insights about the origin of deja vu really. Susumu Tonegawa, a neuroscientist MIT, spawn a number of mice that do not have dentate gyrus, a small part of the hippocampus, which is functioning normally. This section previously known to be associated with episodic memory, the memory of our personal experiences. When come across a situation, dentate gyrus will record visual signals, audio, smell, time, and other signs of the five senses to be matched with our episodic memory. If no matches, this situation would be ‘registered’ as a new experience and recorded for future comparisons.
According to Tonegawa, normal rats have the same ability as men in matching the similarities and differences between several situations. However, as expected, the mice that dentate gyrus was not behaving normally and then had difficulty in differentiating the two situations are similar but not the same. This, he adds, may explain why the experience of deja vu increases with age or the appearance of degenerative diseases such as Alzheimer’s disease: loss or damage to cells in the dentate gyrus due to these two issues can make us difficult to determine whether something is’ new ‘or’ old ‘.
Creating the ‘Deja Vu’ in the Laboratory
One of the things that complicate the investigators in uncovering the mystery of deja vu is the occurrence of natural, spontaneous and unpredictable. The researcher cannot simply ask participants to come and ‘told’ they experience deja vu in a sterile lab conditions. Deja vu generally occur in everyday life, where it is impossible for researchers to continually connect the participant with a brain scanner with a large and heavy. In addition, deja vu occurs rarely made to follow the participants anywhere at any time is not an efficient and effective thing to do. However, some researchers have succeeded in simulating a similar situation deja vu.
As reported by LiveScience, Kenneth Peller from Northwestern University found a simple way to make someone have ‘false memories “. The participants were shown a picture, but they were asked to imagine a completely different picture in their minds. Having done several times, the participants were then asked to choose whether a particular image they actually see or just imagined. It turns out the pictures that participants often claimed only imagine they really see. Therefore, deja vu may occur when by chance an event experienced by someone identical or similar to picture ever envisioned.
LiveScience experiment also reported Akira O’Connor and Chris Moulin of the University of Leeds in creating a sensation of deja vu is through hypnosis. The participants were first asked to recall a series of lists of words. Then they were hypnotized so that they ‘forget’ the words. When the participant was shown a list of similar words, half of them reported a similar sensation like dejavu, while the other half is very confident that they experience is really deja vu. They say this happens because the brain areas associated with his work disturbed by the hypnotic familiarity.