The Economist reports on a fascinating study about the role of generosity in human evolution:

Evidence from economic games played in the laboratory for real money suggests humans are both trusting of those they have no reason to expect they will ever see again, and surprisingly unwilling to cheat them—and that these phenomena are deeply ingrained in the species’s psychology.

I’ve always had a sense that humankind is basically good. As a species, we’ve definitely done some nasty things to each other—much of it in the last few hundred years—but we seem to revert to states of benevolence.

The work done by Leda Cosmides and John Tooby at the University of California, Santa Barbara suggests that extending trust and generosity to complete strangers plays a practical role in our survival. They found that

… generosity pays—or, rather, the cost of early selfishness is greater than the cost of trust. This is because the likelihood that an encounter will be one-off, and thus worth cheating on, is just that: a likelihood, rather than a certainty. [emphasis added]

In this age, the probability that any encounter will be one-off is rapidly approaching zero. Be nice.