Psychology is the scientific study of mind and behavior and psychologists seek to understand all aspects of human thought, experience and action. For example, psychologists interested in decision making might investigate the roles of reason or superstition in the choices people make. Other psychologists might focus on factors that influence emotions ranging from uncontrollable rage, paralyzing fear and suicidal depression to passionate desire and ecstatic joy. Psychologists are interested in the circumstances that might motivate an individual to risk their own life to save others at one moment and commit acts of great cruelty at another. Finally, psychologists apply insights gained through research to practical issues such as treatment of mental illness, increasing job satisfaction, reducing prejudice, increasing recovery from brain injury, preventing crime and developing youth programs that enhance self-esteem and achievement.