A few years ago, Bill McKibben wrote a piece for Science & Spirit magazine in which he explained that "we've spent 99 percent of our life as a species living in a world where you had to react instantly to procure dinner (or to avoid becoming dinner). It is, therefore, extremely difficult for us to take action against, say, global warming because the dangers are a few years away, and the costs are immediate, and we're just not built that way."
He's right. For the most part, we're designed to live in the present, and we attach greater value to immediate rewards than future rewards. But in a new paper, researcher Peter Sozou reports that in some cases, our biology seems designed for the long term. Sozou used a mathematical model to look at how we value future benefits and found that we discount future personal benefits more than we discount future benefits for our community.
As Sozou notes:

This analysis shows that the social discount rate is generally lower than the private discount rate. An individual’s valuation of a future benefit to herself is governed by the probability that she will still be alive in [the] future. But she may value future benefits to her community over a timescale considerably longer than her own lifespan.
Evolution is driven by competition. Caring about the future of your community makes evolutionary sense to the extent that future members of your community are likely to be your relatives.