According to Dale H. Schunk, in his book Learning Theories: An Educational Perspective, theorists and researchers do not have a fixed definition of learning. Schunk (1991) also states that “learning is a lasting change in behavior, or the ability to behave in a given way, that results from practice or other forms of experience”. (page 2). These learning theories are not really learning styles, such as how you learn something; instead, they are more involved in how knowledge is obtained. There are many different ways to approach learning; the three main ways are behaviorism, cognitive constructivism and social constructivism. There were several people who contributed to these theories. In the first learning theory, behaviorism, there were two theorists who studied it. They were John B. Watson and B.F. Skinner. The one who introduced behaviorism was John B. Watson. Watson defined behaviorism as “a natural science which embraces the entire field of human adjustments.” (p. 11 in behaviorism?). Now, BF Skinner believed the same about behaviorism as Watson. Both Watson and Skinner argue that scientific theories should be viewed as stimulus-response rather than insider observation