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Key points
- Déjà vu is the conflict between false familiarity and rational knowledge, not just a feeling of familiarity.
- Déjà vu is a sign of well-functioning fact-checking mechanisms in the brain, not a memory error.
- Fatigue, stress, and dopamine can increase déjà vu likelihood. Exhausted brains are more prone.
- Persistent déjà vu (déjà vécu) may be distressing, linked to conditions like dementia.
Co-authored by Meghan Mcgrogan
Have you ever experienced that uncanny feeling of déjà vu? You know, that strange sensation of having already experienced something happening in the present moment? Déjà vu has long fascinated scientists. Below, we dive into the world of déjà vu research, exploring the latest insights from neuroscience and specifically the work of Akira O'Connor, a neuroresearcher at the University of St Andrews.
More Than a Simple Memory Fault
An oddity of human memory, déjà vu is more than just a fleeting feeling of familiarity. According to O'Connor, it involves a unique awareness that this familiarity is misplaced: "Déjà vu is a conflict between the sensation of familiarity and the awareness that the familiarity is incorrect. And the awareness that you're being tricked makes déjà vu so unique compared to other memorable events." This understanding highlights the phenomenon's complexity and sets it apart from ordinary memory recall.
What’s Happening in the Brain
Déjà vu shares some of the same attributes as delusion. Within a delusion, there is a belief that is not supported by facts, and it continues to be a product of thought for an individual, with the person having a strong belief that cannot be changed or amended with facts of evidence. In the context of déjà vu, forms of delusion involve the misleading effects of perception resulting from illusions.
An illusion is a distortion of the senses resulting from a skewed perception of reality, which is common for many people to experience in the context of déjà vu. Various illusions manifest through our senses (excluding vision) when experiencing déjà vu. Many physical details that seem credible, however, can soon be discredited; in this way, déjà vu is akin to a poorly-executed magic trick.
Contrary to popular belief, déjà vu is not a memory error. Neuroscientists have made significant progress in unraveling the neuroscience behind déjà vu, although no single agreed-upon model exists. According to O'Connor, déjà vu occurs when brain areas, such as the temporal lobe, send signals to the frontal decision-making regions, indicating that an experience is repeating itself.
The frontal regions then evaluate the consistency of this signal with past experiences. If there is no prior experience, the realization of déjà vu occurs. O'Connor explains, "Experiencing déjà vu is probably a good thing for most people. It's a sign that the fact-checking brain regions are working well, preventing you from misremembering events."
Factors Influencing Déjà Vu
Several factors can influence the occurrence of déjà vu. Fatigue and stress have been identified as potential contributors. When the brain is tired, its internal neuronal systems may struggle to regulate themselves, leading to a higher likelihood of misfirings and the sensation of déjà vu. O'Connor notes, "When your brain is fatigued like this, your neuronal firing is more likely to be a bit off and result in déjà vu."
Dopamine, a neurotransmitter associated with signaling familiarity, also plays a role in déjà vu experiences. O'Connor explains, "Dopamine is what’s called an excitatory neurotransmitter. And when we talk about the brain regions signaling familiarity, those neurons would have dopaminergic action." This may explain why drugs that affect dopamine levels, both recreational and medicinal, often induce elevated reports of déjà vu.
Age is another factor that influences the frequency of déjà vu experiences, as younger people tend to experience it more frequently than older individuals. This can be attributed to stronger neural activity and healthier fact-checking frontal regions in younger brains. As we age, our ability to notice errors, including instances of déjà vu, may decline. O'Connor remarks, "It’s exciting that younger people get more déjà vu; older people are normally expected to have more memory quirks."
Déjà vu continues to capture our curiosity, and thanks to the work of researchers like O'Connor, we are gaining a deeper understanding of this intriguing phenomenon. Déjà vu goes beyond a simple memory fault; it reflects the intricate workings of our brains.
Meghan Mcgrogan is the author of The Basic Sixth Sense and the founder of Reyou LLC.
References
O'Connor, A. R., Moulin, C. J. A., & Conway, M. A. (2009). Recognition without identification, erroneous familiarity, and déjà vu. Current Opinion in Psychiatry, 22(2), 165-173.
