It's simpler than this. Turing machines are a beautiful abstraction. Whatever happens in humans is much, much, much, much, much, much messier, on the account of

It's simpler than this. Turing machines are a beautiful abstraction. Whatever happens in humans is much, much, much, much, much, much messier, on the account of it being subject to laws of evolution and working on a scale where various micro-effects can be felt (radiation, Brownian motion and quantum effects anyone?). So even if the Turing machine model is correct (and we don't know that), it's overtly simplified.