This can be easily seen when parents shape good table manners by using praise as a reward for eating behavior that is more adultlike. The children change their behavior because they want to obtain the praise (the reinforcer) and therefore they act more mature and polite. B.F. Skinner expresses this theory in two parts: A behavior followed by a reinforcing stimulus results in an increased probability of that behavior occurring in the future, and A behavior no longer followed by the reinforcing stimulus results in a decreased probability of that behavior occurring in the future. Skinner is the most important American psychologist of the twentieth century, and arguably the most important world psychologist since Freud. Burrhus Frederic (B. F.) Skinner was born on March 20, 1904 in Susquehanna, Pennsylvania, a small railroad town in the northeast corner of the state, just below Binghamton, New York. His parents were Grace and William Skinner; his father was a lawyer, and his mother a strong and intelligent housewife. His upbringing was traditional and diligent; Skinner himself described it as “warm and stable.” Seeking a new direction, he entered graduate school in psychology at Harvard. He got his masters in psychology in 1930 and his doctorate in 1931, and stayed there to do research until 1936. In 1945, he became the chairman of the psychology department at Indiana University. In 1948, he was invited to come to Harvard, where he remained for the rest of his life. He was a very active man, doing research and guiding hundreds of doctoral candidates as well as writing many books. Skinner’s work elaborated a simple fact of life that psychologist Edward L. Thorndike (1874-1949) called the law of effect: rewarded behavior is likely to reoccur. He developed a “behavioral technology”that revealed the principals of behavior control. This allowed him to teach pigeons unpigeonlike behaviors such as walking, playing Ping-Pong etc. As experimental subjects Skinner preferred...