If you've ever had the feeling that a situation was all too familiar, then you've probably experienced déjà vu. The term, which means “already seen” in French, combines objective unfamiliarity with subjective familiarity.
Déjà vu is common. According to an article published in 2004, more than 50 surveys of déjà vu suggested that about two-thirds of individuals experience it at least once in their lifetime. This reported number also appears to be growing as people become more aware of what déjà vu is.
see more
Biology teacher fired after class on XX and XY chromosomes;…
Cannabidiol found in common plant in Brazil brings new perspective…
Most often, déjà vu is described in terms of what you see, but it is not sight-specific and even people who were born blind can experience it.
Déjà vu is difficult to study in the laboratory because it is a fleeting experience. Also because there is no clearly identifiable trigger for it. However, researchers used several tools to study the phenomenon.
Because déjà vu is difficult to measure, researchers have postulated many explanations for how it works. Below are some of the most prominent hypotheses.
Memory explanations of déjà vu are based on the idea that you have already experienced a situation, or something very similar to it. However, you don't consciously remember that you went through it. Rather, you unconsciously remember. That's why it feels familiar, even if you don't know why.
The unique element familiarity hypothesis suggests that you experience déjà vu if an element in the scene is familiar to you. However, you don't consciously recognize it because you are in a different scenario.
The gestalt familiarity hypothesis focuses on how items are arranged in a scene and how déjà vu occurs when you try something with a similar layout.
Some explanations postulate that déjà vu is experienced when there is spontaneous brain activity unrelated to what you are currently experiencing. When this happens in the part of the brain that deals with memory, you can get a false sense of familiarity.
One researcher suggests that you experience déjà vu when the parahippocampal system, which helps identifying something so familiar, randomly fails and makes you think something is familiar when it isn't it should.
Others say that déjà vu cannot be isolated into a single familiarity system, but involves multiple structures involved in memory and the connections between them.
Other hypotheses are based on how quickly information travels through your brain. Different areas of your brain relay information to “higher order” areas that combine the information to help you make sense of the world.
An explanation for déjà vu remains elusive, although the above hypotheses seem to have a common thread: a temporary error in cognitive processing. For now, scientists can continue to design experiments that more directly probe the nature of déjà vu, to be more certain of the correct explanation.
