Author Thomas Erikson explains that there are four key behavior types that define how we interact with and perceive the people around us. Understanding someone's pattern of behavior is the key to successful communication. Erikson breaks down the four kinds of behavior typesReds who are dominant and commanding, Yellows who are social and optimistic, Greens who are laid back and friendly, and Blues who are analytical and precise and explains how to identify and interact with each type of person. Instead of being bogged down with overly technical categorizations, the simple four color system allows you to speedily identify a friend or coworker and adjust how you speak and share with them .