evolution uses whatever hook it can find to tune behavior. Brains of sufficient complexity have to learn, you can't fit even enough information in DNA to manually wire up a brain, and its hard enough to guess how a barin will end up being wired. you can attach a squirrels optic nerve to their auditory cortex and they'll learn to see. (I may have the animal wrong). You can grow a brain completely inside out that will function.

Instincts are deterministic, but learned behaviors.