An example of an external force would be parents rewarding a certain type of behavior, therefore encouraging it further, while an internal force would be hormones. However, functionalists claim that the nature of the universe is such that it is governed by some universal scientific laws, such that every action is caused by a specific prior cause and human action is no exception Burrell and Morgan, (1979). Skinner (1938) argued that all behavior is determined by environmental events and that human beings tend to repeat behaviors that are rewarded. In contrast, the subjective teaching school believes that individuals have free and completely independent will (Choi 2013). Brown (2010) argued that the idea that people's behavior is at the mercy of external forces is inaccurate and that people have free will in the sense that they can choose as they wish