Proponents of ethical altruism maintain that individuals are morally obligated to act altruistically. Type III toxin-antitoxin (AbiQ) systems have been shown to protect bacteria from bacteriophages altruistically. Marshall wrote that religious fervor could influence people to act altruistically. Furthermore, psychologists are expected to altruistically devote some of their time to the community. Thus, the field attempts to discern what causes individuals to act altruistically. He noted the role of social influence and psychological inertia as obstacles to acting altruistically.