What Is Déjà Vu?
Do you ever get the odd sense that you’ve experienced a moment already—even though you know you have not? This is called déjà vu, literally “already seen,” a French term used to describe this odd experience. It sounds like something from the movies or novels, but researchers have found a number of theories to explain this universal mental experience in a rational way.
How Common Is It?
Déjà vu occurs in almost two-thirds of people sometime or other during their lifetime, most commonly in young adults aged between 15 and 25 years. Déjà vu typically occurs in the context of stress, tiredness, or intense concentration. Even though it may be considered a supernatural phenomenon, scientists now recognize it as an experience of memory with cognitive origin.
Memory Mismatch Theory
The most widely used explanation is the theory of memory mismatch. The theory of memory mismatch states that déjà vu happens whenever the brain mixes a new situation with an old one in the past stored in memory. The brain classifies the present moment as familiar due to similarity in layout, sensation, or even small details of visual stimuli.
Dual Processing Theory
One such theory is the dual processing theory. According to this theory, more than one path of processing sensory information reaching the brain is stated. If one of these paths gets delayed, then the information feels like memory and not new experience and the person gets a feeling of false familiarity.
Split Perception Theory
The theory of split perception explains it differently. It is that one can get a glimpse of something for a fleeting moment, without really taking it in, and then, upon viewing it again shortly afterward, the second impression seems familiar because the brain has already subconsciously taken in the first glimpse.
The Role of the Temporal Lobe
Neuroscientists have further attributed déjà vu to temporal lobe activity, the region of the brain engaged with memory. Temporal lobe epilepsy patients often also experience staggering déjà vu feelings before they have a seizure, further corroborating evidence towards suspicion that memory-systems are centrally involved.
Are You Concerned?
For the vast majority, déjà vu is entirely benign and not a sign of any underlying medical condition. However, frequent or ill cases, particularly in conjunction with other symptoms, can suggest a neurological condition that needs to be investigated.
The study of déjà vu instructs us in how fragile and intricate our brain’s memory system really is. Although the feeling itself is still bizarre and fleeting, it is an interesting reminder of how the brain is constantly working to process, store, and make sense of the world around us.
