In Psychoanalysis the Ego is defined as the part of the psychic apparatus that experiences and reacts to the outside world and thus mediates between the primitive drives of the id and the demands of the social and physical environment. My usage is somewhat more relaxed and is simply that part of the mind that reacts without thinking or, thinks fast. Daniel Kahneman the Nobel Prize winning Psychologist and Behavioral Economist has written a wonderful book on that very subject entitled Thinking, Fast and Slow.
I have just finished this exhaustive volume. An invaluable treatise on what others have called the “reactive mind”, fight-or-flight response; that part of our mind that “moves” first. Not only does Kahneman give study after study that illuminates the workings of our “fast thinking” mind or Ego, he gives us ways to counteract the biases inherent in our quick reactions. He calls the antidote essentially “thinking slow”.
I read it twice right away to really let it sink in. It’s that good!