Debate Magazine

Altruism in Religionless Rats

Posted on the 09 December 2011 by Cris

No one who has ever kept rats as pets (as I have) will be surprised by a study that appeared in yesterday’s Science and is getting major media coverage. In “Empathy and Pro-Social Behavior in Rats,” the authors report:

Whereas human pro-social behavior is often driven by empathic concern for another, it is unclear whether nonprimate mammals experience a similar motivational state. To test for empathically motivated pro-social behavior in rodents, we placed a free rat in an arena with a cagemate trapped in a restrainer. After several sessions, the free rat learned to intentionally and quickly open the restrainer and free the cagemate. Rats did not open empty or object-containing restrainers. They freed cagemates even when social contact was prevented. When liberating a cagemate was pitted against chocolate contained within a second restrainer, rats opened both restrainers and typically shared the chocolate. Thus, rats behave pro-socially in response to a conspecific’s distress, providing strong evidence for biological roots of empathically motivated helping behavior.

It may seem gratuitous to point out that rats don’t have religion and I do so only because evolutionary theists often argue that religion evolved because it makes people cooperative and altruistic. Religion, in their view, is an evolutionary adaptation targeted by natural selection because it creates or enhances empathy and pro-sociality.

Those who make this argument usually ignore the fact that empathy, cooperation, and altruism are widespread in nature. Non-human primates are intensely social and quite cooperative, as are elephants and dolphins. Now we can add rats to the list. Religion isn’t necessary to explain these behaviors.

Altruism in Religionless Rats

When confronted with these facts, evolutionary theists usually resort to one of two arguments. The first is that religion makes people more empathetic and pro-social than they would otherwise be without religion. While this may true of post-Neolithic religions which first linked supernatural beliefs to “moral” behaviors, this relatively recent development says nothing about the evolutionary origins of religion.

The second argument is that religion would have made human groups more cohesive and given them a competitive advantage over other groups. While it may be true that post-Neolithic religions functioned as ideological glue for larger groups (group size being the most important predictor of group level success), there is no evidence that human group sizes increased until the after the domestication of plants-animals approximately 12,000 years ago. Again, this relatively recent development says nothing about the evolutionary origins of religion.

Speaking of group size, if you are considering rats as pets — something I recommend — remember they are social and you will need to get at least 2 and preferably 3 or  more, all of the same sex (unless you want lots of babies, which I don’t recommend). For reasons that weren’t clear to me until yesterday, I’ve always had females. The study found that females are slightly more empathetic and pro-social than males.


Bartal, I., Decety, J., & Mason, P. (2011). Empathy and Pro-Social Behavior in Rats Science, 334 (6061), 1427-1430 DOI: 10.1126/science.1210789


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