As someone who is non-religious I can believe this. And yet this does not conflict with one of the four messages in Richard Dawkins' The God Delusion: "Atheists can [emphasis added] be happy, balanced, moral, and intellectually fulfilled" - Wikipedia. This study is just suggesting that religious people are likely to be happier than atheists, for whatever reasons.
I am wondering if religion might be something that might even be selected-for in self-aware organisms. For entities whose cognition is oriented around exploring and explaining things, religion may be adaptive in dealing with things which cannot be easily explained.
Of course, others besides Dawkins have thought through this as well and have looked at various possible explanations for the role and origin of religion:
- "an evolutionary adaptation,
- a side-effect of an evolutionary adaptation, or
- a “mind virus” with no direct evolutionary implications." -- Evolution and Religion: Is Religion Adaptive?
- International Conference on the Evolution of Religion, 2007, Hawaii
- The Biology of Religious Behavior: Religion from the Perspective of Human Ethology. A Symposium. XIX International Conference International Society for Human Ethology University of Bologna, Italy July 13 - 17, 2008.
- Atran, S. 2004. Religion’s evolutionary landscape: Counterintuition, commitment, compassion, communion. Behavioral and Brain Sciences 27: 713-770.
- Bulbulia, J. 2004. The cognitive and evolutionary psychology of religion. Biology and Philosophy. 19: 5: 655-686.
- Bulbulia, J. 2005. Are there any religions? An evolutionary exploration. Method & Theory in the Study of Religion 17: 71-100.
- Dow, J. 2007. A Scientific Definition of Religion. anpere: Anthropological Perspective on Religion
- Fredrickson, B. 2002. How does religion benefit health and well-being?: Are positive emotions active ingredients? Psychological Inquiry, 13: 209-213.
- Wilson, D.S. 2005. Testing Major Evolutionary Hypotheses about Religion with a Random Sample. Human Nature 16: 4: 419-446.
Update March 19: The Science of Religion: Where Angels fear to tread. The Economist, March 18 2008.