Think for a moment, now, that in an animal brain, there is no conscious thought, only reaction. It is a processing of information. Animal behavior changes based upon different reactions, hence different processes. Turtles which reacted by sensing which direction the ocean is and moving towards it tended to survive with a higher frequency. So over time, only the turtles which processed the surrounding information in this such way at that moment in their life remained. Now ask yourself, "Why are people innately afraid of the dark?"