I understand the idea behind studying ethics that if you ever get in an ethical situation, you'll be better prepared. Also, it's fun. Here's my question: At what point do our thoughts become instinct?

For example, I learned to drive and have driven almost every day since. I know that I now have instincts regarding driving.

Is there any discussion like this in the study of ethics? Because if there's no time to choose, our instincts are going to direct our behavior.