I don't know the exact details about it. I just knew something about smells being in a similar section to the brain and triggering memories. I just started anatomy a week ago and it was mentioned in a movie.
I don't disagree with you. But I think there has to be something else that can form their personalities as not all snakes and reptiles act the same way. Those effects that run them off course of their pure instinctual behaviors makes it possible for other environmental factors to have an effect on them.
Technically, if a snake was run by pure instinct alone, wouldn't they all act exactly the same no matter what the situation?