We Finally Know What Causes Deja Vu
Scientists have finally figured out what is actually happening in your brain during deja vu. A new study in the journal Memory is the first to capture brain scans of healthy volunteers during deja vu, and the findings flip the popular explanation on its head. For decades deja vu was assumed to be a memory glitch, a misfiring that confuses something new for something familiar. Research from Dr. Akira O'Connor at the University of St Andrews tells a different story. Rather than a malfunction, deja vu appears to be the brain's conflict-monitoring system doing exactly what it is supposed to do. When the sense of false familiarity clashes with the knowledge that an experience is genuinely new, the brain flags the contradiction. The anterior cingulate cortex, a region that catches competing signals and flags that something needs review, lit up at precisely those moments. Strikingly, the more certain people were that an experience was new, the more likely they were to report deja vu.
The findings also explain a long-standing puzzle: why deja vu decreases with age rather than increasing. If it were a memory error, older and less reliable brains should experience it more. But if it is the frontal conflict-checking system at work, the decline makes sense, since those systems naturally weaken with age. The research also sheds light on deja vecu, a condition linked to dementia where people become convinced they have already lived through events. In healthy brains the reality check wins. In deja vecu it does not. Deja vu, it turns out, is not your brain slipping. It may be your brain catching itself in the act.
