Psychologists that implement behaviorism observe the relationship between stimuli and observable behavioral response. In other words, it is the study of cause and effect. Many believe that most human behavior is the result of conditioning. B.F. Skinner believed that human behavior is controlled by rewards. He also believed that thinking is not needed to explain why people take certain actions. Basically, the belief held is that we do certain things because there is a reward that we have been conditioned to expect. There is however a less strict form of behaviorism that may explain more complex human behavior.
Cognitive behaviorism combines cognition (thinking) and conditioning to explain human behavior. A cognitive behaviorist would say that we watch tv because we are rewarded with a pleasurable escape but also we do so because we may think that we will learn something from the documentary that we watch.
There seems to be much credit due to behaviorists, as many questions about human behavior have been answered by this field of psychology. Using the principles of rewards and conditioning have been very useful in the field of behavior therapy where serious strides have been made in correcting problem behaviors.