" In this way, each of us has unique neural networks, which are formed, reinforced, and constantly updated by the eclectic circumstances of our lives. Once circuits are formed, that increases the chances the same circuits will fire in the future. The neural networks embody our experiences and in turn guide future action. They contain the unique way each of us carries himself in the world, the way we walk, talk, and react. They are the grooves down which our behavior flows. A brain is the record of a life. The networks of neural connections are the physical manifestation of your habits, personality, and predilections. You are the spiritual entity that emerges out of the material networks in your head. "

― David Brooks , The Social Animal: The Hidden Sources of Love, Character, and Achievement