Final answer:
Maslow's hierarchy of needs is the widely accepted theory of human behavior that serves as the main model in this course, emphasizing the potential good in all people and the growth toward self-actualization.
Step-by-step explanation:
The theory of human behavior that is most widely accepted and serves as the main underpinning model in this course is Maslow's hierarchy of needs. Abraham Maslow's theory is a humanistic approach to psychology, which focuses on the potential for good in all people. Maslow proposed that human beings have certain needs that are met in a certain order, with the highest need being for self-actualization. His theory suggests that our emotional and behavioral issues may stem from unmet hierarchical needs, emphasizing the growth potential of healthy individuals. This differs from theories such as Watson's behaviorism or Freud's psychoanalytical theory, which focus on more deterministic views of human behavior.