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Evolutionary psychology, or the study of how evolution shapes human behavior, is a controversial field, particularly when it comes to gender. To discuss evolutionary psychology is to discuss certain innate differences between men and women, and given the history of pseudoscientific “reasoning” about gender differences that has contributing to men’s dominance over women, it’s understandable that people are uncomfortable with this subject.

That doesn’t mean all evolutionary-psych findings should be discarded or questioned, of course. But it does mean it’s important to be vigilant and skeptical about them and to not automatically assume theories that fit what we think we know about sex differences are correct. All of this is nicely summed up by a tweetstorm from earlier today.

It started with a blog post published earlier this week with the title “The ideological opposition to biological truth,” in which Jerry Coyne, a well-known evolutionary biologist and skeptic who is the author of Why Evolution Is True, laid into what he sees as a “blinkered” approach to sex differences on the political left:

To claim that there are no evolutionary differences in behavior and psychology between men and women is fatuous. The data show otherwise, though of course for most traits we don’t know if it’s genetic. But the default hypothesis, based on observation of other species (especially primates) is that at least some psychological and behavioral differences will be based on genes that evolved via selection in our ancestors. Why is the brain immune to evolved, sex-specific differences but the body is not?

This is a compelling argument. It doesn’t make sense to think that humans are just about the only species with no differences, when it comes to innate traits or tendencies (at the level of averages — there will always be extremely aggressive women and extremely nurturing men), that aren’t “baked in” to our biology in certain ways. But it’s a compelling argument because he hedges — Coyne thinks there are “at least some psychological and behavioral differences” that fit in this category, not that all of them do. Nature isn’t the whole deal.

Later in his post, he points out that in “virtually all species of primates,” as well as in some other types of animals, males tend — again, on average — to be bigger than females. And there is what he views as a straightforward likely explanation for this:

It reflects evolved male behavior: the tendency of males to compete for females, and the advantage of large body size in that competition. Whether the advantage be in direct competition, so that the larger you are the more you can fight off other males (gorillas, elephant seals), or in female choice, so that females choosing large males can gain protection for her young from marauding males (also gorillas), the difference in size reflects something almost universal among animals: males, who have cheap gametes, must compete for females who have expensive gametes and invest more in reproduction. And that is why, in study after study in humans, male sexual behavior shows promiscuous mating, while females are more selective. That’s not necessarily all biological, but some of it surely is given that our closest relatives show the same behaviors and that there is no such thing as The Gorilla and Chimpanzee Patriarchy.

After providing some more evidence that “the larger size and strength of males is reflected in their behavior … and was almost certainly promoted by sexual selection,” Coyne bemoans the fact that so many on the left refuse to acknowledge it. “To deny that the differences between human males and females in size and strength are evolved is to deny at the same time that differences in behavior between males and females is evolved,” he writes. “Only the blinkered ideologue would do that. Sadly, these ideologues continue to promote antiscientific ideas on the Internet.”

Earlier today, Holly Dunsworth, an “evolution-minded anthropologist” at the University of Rhode Island and Science of Us contributor, responded to Coyne’s article with an illuminating tweetstorm, some of which went as follows:

Evolution is true but people with large followings should fear the cultural consequences of their adaptive tales. https://t.co/VMtOGBbtH5 — Holly Dunsworth (@HollyDunsworth) December 16, 2016

It's not that these facts aren't necessarily facts, or whatever. It's that it's too simple and biased toward some stories, ignoring others. — Holly Dunsworth (@HollyDunsworth) December 16, 2016

What about the other side of the sexual dimorphism story? The women? Selection could well be the reason they stop growing before men. — Holly Dunsworth (@HollyDunsworth) December 16, 2016

Perhaps men can make babies while growing, but perhaps women can't. Energetically, metabolically. So reproduction wins over growth. — Holly Dunsworth (@HollyDunsworth) December 16, 2016

Why doesn't this (and other tales) fit alongside the big-aggressive-males-take-all explanation for sexual dimorphism? #evolution — Holly Dunsworth (@HollyDunsworth) December 16, 2016

Knowledgeable people aren't objecting to facts. They're objecting to biased story-telling and its annoying and harmful consequences. — Holly Dunsworth (@HollyDunsworth) December 16, 2016

Not only is it absent, but selection on women's bodies be the driving force (if such a thing could be identified) ... — Holly Dunsworth (@HollyDunsworth) December 16, 2016

...and it's as if women don't exist at all in these tales except as objects for males to fight over or to fuck but it's nice to have choice! — Holly Dunsworth (@HollyDunsworth) December 16, 2016

As long as evolution, especially human evolution, is publicly championed like that, it's not going to catch on among thoughtful kind people. — Holly Dunsworth (@HollyDunsworth) December 16, 2016

Stories and stances like Jerry Coyne's are part of what's driving me away from studying human evolution. But maybe I need to stay AND FIGHT. — Holly Dunsworth (@HollyDunsworth) December 16, 2016

This is actually a really important response for people hoping to better understand the controversy over evolutionary psychology. To Dunsworth, Coyne is blurring together two different categories of claims: claims that there are evolutionarily driven differences between men and women, and specific stories explaining those differences. Coyne claims the size difference between men and women is driven, or driven primarily, by competing for and protecting females. Dunsworth says, in effect, Not so fast — why are we so quick to latch onto that particular story, when there might be others?

There really are people who deny there are any innate, evolutionary driven differences between men and women, and as Coyne points out this belief tends to come out of certain political movements who don’t view such differences as compatible with feminist or progressive beliefs and goals. But Dunsworth and other principled, informed critics of evolutionary-psychology findings aren’t the ones denying any differences between men and women; they’re just asking that the stories we tell be carefully thought-out, tested, and so forth. “I’m not denying [those differences],” Dunsworth told me in a Twitter DM. “But I am denying that story being the only (as if it’s the only) part of the story of sexual dimorphism (and the same for so many evolutionary tales of other human traits). His is the simplified status quo and it’s inaccurate in its simplicity. And us ‘liberals’ refusing these over-simplified, biased stories is not denying science.”

In Dunsworth’s view, all she is asking for is some nuance and, well, skepticism. “People love to boil complex processes down to their preferred (intentional or not) story,” she wrote, “with some in leading roles and others completely absent, and we don’t have to take that anymore.” Her tweeted example about growth nicely captures this: It could be that Coyne’s aggressiveness story leaves out important details about why men are bigger than women, or fails to explain certain aspects about that differences. Overall, it certainly seems like people are quicker to latch onto evo-psych stories that reinforce certain views of men and women.

Now, maybe, in the long run, evo-psych stories that liberals find “problematic” will have such overwhelming evidence behind them that they will win, in the scientific-process sense. Even if they do, as Coyne points out, there’s an important is/ought distinction here — you can accept that we’re evolved in a certain way without endorsing that type of behavior, and such knowledge can in fact help design societal structures more likely to strip us of bits of evolutionary baggage that are no longer adaptive.

But for now, there’s still a lot we don’t know about the connections between evolution, behavior, and sex differences. We shouldn’t focus too tightly on any one set of stories, and we also shouldn’t act as though I don’t believe in any innate sex differences between men and women is the same sort of statement as I don’t believe this particular story about sex differences between men and women tells us everything we know. The former statement is silly, while the latter reflects sound, open-minded scientific thinking.