Interesting. I (also in my 40s) sometimes experience the vividness of reality in a higher quality than usual, and I vaguely recall that my visual experience was always this vivid when I was younger. Most of the time now it seems to be a bit dulled down. I always thought that this is because I probably need glasses. It might also be stress related.

What would cause such a change, and would there be an evolutionary explanation for it? Could it be related to vision only, or does it apply to other sensory input as well?