Editorial
Nature 455, 1007-1008 (23 October 2008) | doi:10.1038/4551007b; Published online 22 October 2008
A look within
A series of Essays examines what science has to say about being human.

In the spirit of fostering dialogue between disparate fields of research, Nature has commissioned a series of Essays that asks how discoveries in psychology, anthropology, genetics, neuroscience, game theory and network engineering are altering our understanding of particular human characteristics, or of issues that are central to human life. Starting this week with religion (see page 1038), and appearing every two weeks for the next five months, these Essays move from human prehistory to look at how we operate within self-made highly interconnected cities and communication networks.

Cumulatively, the series indicates that the interface between science and society is no less thorny now than it's ever been; revelations about our appetite for warfare in an Essay on conflict, for example, will make for uncomfortable reading. But overall, practitioners from diverse areas of research deliver an optimistic message about how we may learn to manage ourselves more effectively as a result of knowing ourselves better.

It is a small step from having this capacity to bond with non-physical agents to conceptualizing spirits, dead ancestors and gods, who are neither visible nor tangible, yet are socially involved. This may explain why, in most cultures, at least some of the superhuman agents that people believe in have moral concerns. Those agents are often described as having complete access only to morally relevant actions. Experiments show that it is much more natural to think "the gods know that I stole this money" than "the gods know that I had porridge for breakfast".

In addition, the neurophysiology of compulsive behaviour in humans and other animals is beginning to shed light on religious rituals. These behaviours include stereotyped, highly repetitive actions that participants feel they must do, even though most have no clear, observable results, such as striking the chest three times while repeating a set formula. Ritualized behaviour is also seen in patients with obsessive-compulsive disorders and in the routines of young children. In these contexts, rituals are generally associated with thoughts about pollution and purification, danger and protection, the required use of particular colours or numbers or the need to construct a safe and ordered environment.

We now know that human brains have a set of security and precaution networks dedicated to preventing potential hazards such as predation or contamination. These networks trigger specific behaviours such as washing and checking one's environment. When the systems go into overdrive they produce obsessive-compulsive pathology. Religious statements about purity, pollution, the hidden danger of lurking devils, may also activate these networks and make ritual precautions (cleansing, checking, delimiting a sacred space) intuitively appealing.

Finally, studies of social and evolutionary psychology demonstrate a specifically human coalitional capacity, which has an impact on religion. Humans are unique among animals in maintaining large, stable coalitions of unrelated individuals, strongly bonded by mutual trust. Humans evolved the cognitive tools to achieve this. They know how to gauge others' reliability. They can recall episodes of interaction and infer what people's characters are like. They can emit and detect costly, hard-to-fake signals of commitment.