Can human behavior be predicted

Yes, human behavior can be sometimes be predicted.

There is a very interesting theory of personality types based on just 3 personalities. It is called the Wakefield Doctrine (the theory of Clarks, Scotts and Rogers). It is a reasonable, easy to understand and useful tool. Once you can see the world through the eyes of another, behavior becomes understandable. What's more, one of the more beneficial (and fun) aspects of the Doctrine is the ability to predict the behavior of each (Clark, Scott or Roger) in any given situation. The Wakefield Doctrine lets you see the people in your life in a way that will have you saying, "So that's why they act that way!"