Autho r Thomas Erikson explains that there are four key behavio r types that define how we interact with a nd perceive the people around us. Understa nding someone’s pattern of behavio r is the key to successful communication. Erikson breaks down the four kinds of behavio r types—Reds who are dominant a nd comma nding, Yellows who are social a nd optimistic, Greens who are laid back a nd friendly, a nd Blues who are analytical a nd precise—a nd explains how to identify a nd interact with each type of person. Instead of being bogged down with overly technical catego r izations, the simple four colo r system allows you to speedily identify a friend o r cowo r ker a nd adjust how you speak a nd share with them.