Hum... I have no model for what actually happens. It's just that simulated annealing appears quite often on the biologic world, we never found any coordination communication channel that could create something more "intelligent" (AFAIK, there are just a few "neighborhood to global" analog signals available), and there isn't a multiplicity of attempts interacting with each other (again, there is no channel for that) that would lead to a parallel evolutionary strategy.

Also, when we learn a mechanical task, our errors tend to cool down around our successes, instead of following a direction.

But again, I have no idea of any mechanism that is there. It's more because all the others seem to have been eliminated.