See also my earlier post: "A monopoly on moral behaviour?"
For some, there is no morality without religion. For others, religion is merely one way of expressing and legitimating one's moral intuitions. Religion can be linked to morality in different ways: moral principles are either decided by gods or by ancestors, or saints and holy individuals provide a model to be followed. Alternatively, gods and ancestors are regarded as interested parties that pay attention to what people do and people thus feel that their moral choices are never merely a private matter.There are endless often pointless web arguments about whether religion is necessary for humans to be moral. But surely that's the wrong question. I think most of us would agree that humans have an innate sense of morality. The really important question is surely whether this is God given. I hold the belief that it is not, but I cannot prove that, any more than someone else can prove that it is.
It is important to distinguish explicitly held religious beliefs and affiliations from religious intuitions. Bering, for example, presents experimental evidence that even non-religious subjects intuitively consider some mental states and processes, such as emotions, more likely to continue after death than others, such as hunger. Bloom argues that all humans are intuitive dualists in the sense that we feel our self to be the owner of the body, but we are not the same as our bodies. Thus, in folk psychology, the death of the body does not mean the cessation of personhood. Furthermore, because human reasoning is characterized by a promiscuous teleology, a capacity that causes us to see meaning and intentionality in everything that happens, we automatically postulate an agent as an explanation of various events; often this is some god -like concept.
Arguably, these tendencies make religious beliefs contagious in the sense that they are easy to spread and propagate because they functionally resonate with many of the basic operations of the mind. Consequently, they are also easy to use in moral reasoning. This does not mean, however, that there is a necessary link between morality and religion. There is evidence that at least some religious concepts and beliefs need certain cultural input in order to become adopted and to persist. The Vezo of Madagascar, for instance, seem to have two conceptions of death. Guided by their everyday experience, they construe death in biological terms as the breakdown of all vital functions, but see it as the beginning of a different form of existence in a ritual context. These two conceptions of death are activated in different contexts, and thus the Vezo do not feel that there is a tension between them.
Thus, although it seems undebatable that religiously colored intuitions can affect moral reasoning, and that religious primes can affect prosocial behavior, these observations do not license the conclusion that the mechanisms are specific to religion, nor that religion provides the central explanatory factor. Even when the intuitive content is interpreted as religious, the mechanisms that support reasoning are more general in scope.