Feeling of Familiarity

Déjà vu if translated means “already seen” in French. As a concept, it combines the feelings of familiarity and objective unfamiliarity with subjective familiarity. It is called experiencing a déjà vu.

Déjà vu is common phenomenon. According to research published in 2004, 50+ surveys on déjà vu suggested that about 66% of individuals have experienced déjà vu at least once in their lifetime. Many of them reported experiencing it more than once. These numbers also appear to be increasing as people become more and more aware of what déjà vu is.

More often than not, déjà vu is described in terms of what someone sees, but it has nothing to do with sight, even people who were born blind have reported experiencing it.

How to measure Déjà vu?
Déjà vu is problematic to study in the laboratory because it is fleeting, and also because there is no marked and identifiable trigger for it. Because déjà vu is hard to measure, researchers have proposed many theories explaining how it works. These explanations mainly fall into two categories - Memory Explanations and Neurological Explanations

Memory Explanations

1. Single-element familiarity
The single-element familiarity hypothesis suggests people experience déjà vu if one element from the setting is familiar but they don’t consciously recognize it or are unable to point it out because of its different setting.

2. Gestalt familiarity
The gestalt familiarity hypothesis focuses on how rather than the what. If items are organized in a scene in a certain way, déjà vu occurs when the mind experiences something with a similar layout. One plus point of the gestalt similarity hypothesis is that it has the potential to be more directly tested.

Neurological Explanations

1. Spontaneous brain activity
Some explanations suggest that déjà vu is experienced when there is spur-of-the-moment or a spontaneous brain activity unrelated to what the brain is currently experiencing. When that happens, part of the brain dealing with memory can have a false feeling of familiarity.

2. Neural transmission speed
Another hypothesis is based on how fast the information travels through the brain. Different parts of the brain transmit information to other areas that combine all the different chunks of information to help it make sense of the world. If this complex process is disrupted in any way – like one part sending information relatively slower or more quickly than it usually does – then the brain interprets the surroundings incorrectly.

But Which Explanation is Correct?
An explanation for déjà vu remains vague and intangible, though the hypotheses do have one thing in common: a temporary error in cognitive administering. Currently, theorists continue to design experiments to more directly investigate the nature of déjà vu, to reach a more concrete explanation.

By: Deeksha Goyal