Evolved Altruism

I hear the same question asked again and again in different guises. Why do we spend our valuable tax dollars on international aid? (See Edin’s post on the topic.) Why should we, as a people, spend resources on Food Stamp programs, Social Security, Medicaid, Medicare, and/or any other of a host of ways we help out people who can’t (or, in a worst-case scenario, won’t) minimally-thrive without it? Why should I help that guy; what has he done for me (lately)?

Well, I aint no politician (if you’ll pardon the vernacular). And I aint no scientist, per se, but for questions like this I tend to fall back on my philosophy degree, which had an academic concentration on psychology and thus included lots of psychology classes. I’m fascinated by the relatively young field of evolutionary psychology.

Evolutionary psychology (EP) basically says that the way we think can have a bearing on whether or not we survive long enough to have kids who themselves survive long enough to have their own kids, and so on. So, ways of thinking that help us pass our genes are selected for; those that hurt the process are selected against.

It can be a controversial field of study, because too many people have used it to justify bad behavior based on the “sexually dimorphic” ways of thinking that have to do with reproductive strategies. “Men and women think differently,” goes the argument, “so it’s perfectly okay for me to be unfaithful.” To which, let me say: just, no. That’s not how it works, fellas.

But, skirting that controversy, evolutionary psychology suggests that certain patterns of thinking—and even certain emotions—came into existence in the human animal because they helped us survive in the environment that we did most of our evolving in. Good at spotting patterns (even when there are no patterns actually there)? That’s so you can use patterns found in the environment to survive. Scared? Your body’s getting amped up for fight-or-flight. Proud, or ashamed? That probably has something to do with maintaining your status within your “tribe.”

And let’s talk about this “tribe” and a thing called “Dunbar’s Number.” Professor Robin Dunbar made some observations about the number of social relationships a primate is able to maintain, and noted a correlation to the brain-mass of the particular species of primate. He did some math, hypothesized that the number for humans might be around 150, and over the years that hypothesis has been tested in a variety of ways by a lot of people and has held up pretty well. You can read all about that if you like.

The suggestion here is that your “in-crowd”—the people you know well and who form the important part of the social structure that supports you—is no larger than about 150. Our brains just aren’t big enough for us to remember enough details about more people than that for us to maintain meaningful relationships with all of them.

Which brings me back around to my question about altruism. Looking out for oneself—our basic survival instinct—is a biological imperative. Looking out for one’s offspring is a genetic imperative that, remarkably, sometimes seems to be able to outweigh the survival instinct. But what about self-sacrifice for extended family members, those not directly carrying your genes forward to the future? And what about your in-group, your 150 closest friends? And what about the rest of humanity, those 7 billion other people who aren’t close enough to you to matter? Ought we to sacrifice our personal well-being for them, at all?

From a strictly EP viewpoint, the answer is “when the conditions are right, yes.” They have “equations” for it, but to me it makes more sense to write out what the equations mean.

First of all, for kin, people in your extended family, self-sacrifice makes sense when the amount it hurts you is less than the amount it helps your family member times just how closely they’re related to you. The measurement units are a bit abstract, so let’s use an exaggerated example: if you have 100 potatoes and your mom’s sister’s daughter has 1 potato, it helps your genes if you’ve learned to give her 1 of your potatoes, and that degree of altruism is selected for. (Where’s the break point—2 potatoes, 20? For purposes of this discussion, it doesn’t matter.)

Vincent and Jules are best buddies

Vincent and Jules are best buddies.

For people you know about (say, your extended circle of friends), EP suggests that the reputation of the recipient has a bearing on whether self-sacrifice is smart. How likely are they to do the same for you? Back to our potato example: Jules and Vincent are best friends, though biologically as distantly-related as can be. Times are tough one year, and Vincent is down to his last potato. Jules has just enough potatoes to adequately feed himself until the spring harvest, but he gives half of his potatoes to Vincent anyways. Though hungry, they both live through the lean months.

Ten years after, another hard year comes along and this time it’s Jules who is out of goat’s milk. (Let’s suppose a coyote attack.) Vincent has only two good milking goats, but Jules’s reputation with Vincent is great. EP suggests that Vincent giving one goat to Jules is the smart move, and that we’d expect this degree of altruism to be selected for.

Takeaway: as a species, we’ve learned that it’s good to help out people who have a reliable reputation for helping people out.

Finally, what about the other 7 billion strangers on the planet? Why—or how much—should we help them? If we have no information, good or bad, about someone else’s reputation, EP suggests that the equation hinges on the likelihood that we’ll ever encounter them.

So there you have it; your choices are on the table. Do we provide aid internationally because we believe that the benefits (such as stability in foreign regions) outweigh the costs? Or do we do it as a kind of charm offensive, a way to build a good reputation in hopes that other nations will help us out when we’re facing tough times? Or do we believe we’ll never encounter the people we’re helping, and therefore ought to keep our enormous surplus of potatoes and goats to ourselves?

I’d like to believe that we’ve been made to be better than that.


Late-breaking! Scientific American published a relevant article a couple of days after I wrote this. See Forget Survival of the Fittest: It Is Kindness That Counts.

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