Sources for moral decision-making are multiple and cover a number of theoretical, physical and philosophical fields of investigation. While traditional beliefs often privilege sources of ethical authority as the basis for moral decision-making, authorities such as religion and rationality, other research suggests that biological and psychological factors may also play significant roles.
One of the oldest and most pervasive sources of moral decision-making is religion. Religion not only tends to outline what is right and wrong, but also customarily prescribes behaviors that allow the individual to navigate through tough choices in their daily lives. In other words, it provides codes of conduct from which people can formulate the most basic ethical decisions. Moral philosophy is another source and appeals to human reason and recognition of people's common humanity rather than faith. In both cases however, moral decisions are deduced from broader belief systems which propose answers for most, if not all, situations. Individual societies and cultures also create their own ethical norms, ones which can have a profound impact on people's worldview and choices, with or without religion being the primary motivator.
These sources are not the only ones recognized by scientists however. According to Princeton University, scientists also consider emotions as a possible site of moral decision-making. Some researchers have observed, for example, that moral questions induce "a greater level of activation in emotion-related brain areas." This and related research suggests that moral decision-making may be linked to neuro-scientific causes alongside rational or faith-based contemplative ones.