Wagering on diversity

Researchers regularly place bets. Not in the sense of plunking down money, but in the sense of deciding—often on hunches—that one outcome is more likely than another, that certain avenues are particularly promising, that some uses of time are fruitful and others feckless. Bets like these guide our work.  

One wager that many of us in the behavioral sciences make, whether we realize it or not, is about human universality and diversity. At issue is whether we think people are broadly the same the world over—the universality stance—or differ in deep ways according to place and time—the diversity stance.

It’s a stance with consequences. Which way we lean guides what phenomena we focus on, what research we value, and, especially, what populations we study. If one inclines toward the universality stance, it’s easy to feel justified in studying “humans” by focusing on Western, Educated, Industrialized, Rich, Democratic (aka WEIRD) subjects, usually North American Undergraduates (aka NAUs), who are speakers of Standard Average European (aka SAE) languages. If humans everywhere are basically the same, the reasoning goes, why bother trekking to the ends of the earth—or even off campus—to recruit participants? In contrast, if one inclines toward the diversity stance, one is probably uncomfortable saying much about the whole of our species based on convenient samples. One is motivated to go further afield, on the understanding that behaviors that look like human nature in a lab in California could prove to be WEIRD quirks.

Part of why these diametrically different stances persist is that we simply don’t know the relevant facts. Only a tiny sliver of human behavioral phenomena have actually been studied systematically across groups. In a few cases, we’ve learned that humans appear to be largely the same everywhere—sometimes remarkably so. (Who would have thought that the English word ‘huh?’ has close cousins in sound and meaning across dozens of languages?). In other cases, we’ve learned that humans vary to a considerable degree, sometimes in unexpected ways. (Who might have guessed that speakers of some languages operate with “basic smell words,” much as English speakers operate with basic color words?). However, in most cases, for most behavioral phenomena, we just don’t yet know—the extent of diversity is anyone’s guess.

Given this uncertainty, how should researchers in the behavioral sciences proceed? Should we wager on universality or on diversity? Is one of these bets more likely lead to a greater understanding of our species? I would argue the answer is a resounding yes. Where we put our metaphorical money matters, and we should put that money on diversity.

One argument for the diversity bet goes like this. Simplifying a bit, imagine two sharply opposed wagers—“much diversity” or “not much diversity”—with one of these categorical outcomes being, in fact, correct. Let’s also assume that the wager we make guides our research (not such a big assumption). Now let’s construct a space of these bets, our corresponding behaviors, and the eventual outcomes.

If we put our money on “much diversity” and this proves correct, we’re fine. We spent our careers in far-flung corners of the globe, sampling across the kaleidoscope of humanity, sometimes in trying circumstances. We did our best to document human diversity and learn from it; we upturned a few simple-minded notions about human nature; and we helped develop a better understanding of the range of mechanisms that shape human behavior.  

If we bet on “not much diversity” and this turns out to be true, we’re also in good shape. We spent our careers in the cozy confines of the university subject pool, but, as it turns out, we would have found more or less the same things in other populations. Bonus: we saved substantial resources in the process, since working with inconvenient samples is inconvenient.

But, as any researcher knows, the universe does not always cooperate. Sometimes our best-laid hypotheses are flatly contradicted; sometimes our theories come undone. So what if our bets about the extent of diversity prove wrong?

Perhaps you have begun to intuit the analogy I’m developing, to one of the most famous intellectual bets in history: Pascal’s wager. The bet is named after the 17th century French polymath, Blaise Pascal. Like many of his contemporaries, Pascal was invested in the question of whether the Christian God really exists. By building a grid of possibilities, he constructed an argument that we should all believe in God.

Pascal's wager.jpeg

In Pascal’s grid, there are two possible beliefs (God exists or does not) crossed with two possible realities (God really exists or does not). In each cell, there is a consequence of acting on these beliefs. If you believe God exists, and you’re right, Pascal argued, then you’re fine—you hopefully will have lived your life with an eye toward currying his favor. If you believe God does not exist, and you’re right, then you’re still fine—you didn’t waste time in a pew, and probably enjoyed a few more earthly delights than you otherwise would have. So as long as you’re right, you’re gold.

But what if you’re wrong? If you believe God does exist, and you’re wrong, you’re still okay—you missed out on some fun but that’s not the end of the world. However, if you believe God does not exist, and you’re wrong, your prospects are bleak—in fact, you’re facing eternal damnation.

Now back to our real concern: whether we in the behavioral sciences are better off betting on “much diversity” or on “not much diversity.” As in Pascal’s wager, either bet is fine if it proves correct. And if we wager on “much diversity” and turn out to be wrong, this is not such a bad thing. We could have stayed down the hall, working with the WEIRD model organisms close to hand, but instead we ventured out. We had a few field misadventures to tell our friends about and more than a few enriching life experiences. And, in fact, we contributed to the project of providing evidence for human universality rather than simply taking it on faith.

Kensy's wager.jpeg

But if we wager on “not much diversity” and turn out to be wrong, the outcome is not so benign. We stayed in the lab; we learned some interesting things about WEIRDos, NAUs, and SAE speakers. But we also likely came up with some erroneous explanations for the phenomena we’re interested in. In particular, we may have settled on accounts that downplay the critical role of cultural practices and ecological circumstances in shaping human behavior. What is especially unfortunate about this misplaced bet is that the diversity we didn’t bother to study is vanishing fast. Future generations of researchers may not have the chance to bet again, to replay the tape and take diversity seriously the second time around. The price of wagering on “not much diversity,” in other words, may be eternal ignorance.


1. Another reason these polarized positions persist is a matter of taste. Given the same set of facts, some observers will intrinsically be more interested in what those facts suggest about universality, about our common core; others will want to dwell on what the facts imply about our inherent malleability. This difference in taste seems to be, in part, a matter of what kinds of mechanisms—biological, cultural, ecological, and so on—researchers find most fascinating. 

2. It’s not just a matter of placing metaphorical money, of course. Funding agencies place bets, too.

3. Permit me to point out a wrinkle: we simply can never settle questions about universality and diversity by staying home. This tack won’t satisfy the relativists, and it shouldn’t satisfy the universalists either. Perhaps it is unfair to say that universalists are inclined to stay home; in fact, there are plenty of scientists of such a bent who are driven to demonstrate universals rather than simply assume them.

4. Caveat: I’m leaning on an informal understanding of Pascal’s wager, as it has been taken up in popular culture, not one based on a close reading of his writings. For a thorough discussion of Pascal’s original argument and reactions to it, see, for instance, ‘Waging war on Pascal’s wager.’ Further caveat: in the service of my analogy, I’m down-playing one aspect of Pascal’s argument. He argued that when you choose to believe in God and get this right, you’re not only “fine,” you are headed for infinite, eternal happiness. Subtle difference.

5. I’m not tacitly arguing for Pascal’s original wager. In fact, I don’t find compelling. The force of his argument—and analogues of it— hinges on the plausibility of either state of the world, given what we know.