Lamont's father has been out of work for more than a year, and, as a result, his parents argue constantly. Despite his stressful home environment, Lamont is highly engaged in school and maintains a positive attitude. On the other hand, Lamont's younger sister, Raquel, is prone to fighting at school and her grades are poor. That Lamont and Raquel are so different despite growing up in the same family provides support for the theories of: