Theories of deja vu formation are a bit like toothbrushes, says Akira O'Connor. His theory is that in the middle of your brain every now and then there are these misfires which make you think that you recognize a situation. And so what it does instead is send out a fact checking signal essentially. This can sort of tell you a lot about how our brains develop and deteriorate over the course of our lives. Because young people like teenagers and people in their 20s are more likely to experienceDeja vu because their brains are especially active during development.