The sociological religion of no biological differences between the sexes

October 6, 2016 • 9:30 am

As a biologist, I’ve learned that there are two related issues that are taboo for academics to discuss openly. The first is the issue of “races”—or genetic differences between human populations. Cultural anthropologists tell us that races are “social constructs.” Well, there’s a bit of truth in that, insofar as there is no finite number of races that can be unambiguously demarcated from each other. But there are genetic differences between groups, and clustering algorithms can divide populations into five or six fairly distinguishable groups corresponding to their geographic localities. Those differences in marker genes undoubtedly evolved via either genetic drift or natural selection in early human populations that were geographically isolated.

But the issue of whether there are genetically-based differences in behavior, physiology, mentation, and other non-physical attributes of populations is simply off the table. It’s not just that we shouldn’t investigate them (for one can make a case that such research might itself have invidious social consequences), but that those differences don’t exist. I’ve even heard people called “racists” by cultural anthropologists—one of the worst fields for ideologically motivated scholarship— simply for suggesting that there might be behavioral genetic differences between human groups. You can discuss the issue, but there’s only one position considered acceptable.

My own take is that the separation of human subgroups has been so recent that there hasn’t been a lot of time for extensive genetic differences to evolve, though clearly there’s been time for marked physical differences to evolve. And it’s clear that human intermixing, facilitated by transportation and increased mobility, will tend to efface all of these differences. But we shouldn’t assert that any trait beyond the most obvious physical differences between groups shows complete equality among them.

When it comes to the sexes, though, it’s a different matter. In the hominin lineage males and females have been coevolving (either cooperatively or antagonistically) for 6 million years or so—ample time for differences in behavior, wants, thought patterns, and so on to evolve, just as morphological differences between men and women have clearly evolved. Do those genetic differences in thought and behavior exist? I suspect they do, at least for traits connected to sexuality and sexual behavior. Just as animals ranging from flies to mammals show consistent (though not universal) patterns of male/female differences in sexual behavior—differences explainable by sexual selection—so I expect the human lineage evolved similar patterns. After all, males are larger and stronger than females, and you have to explain that somehow. How do you do so without explaining evolved differences in behavior—probably based on sexual selection?

Yet the idea that males and females show evolutionary/genetic differences in behavior is also anathema in liberal academia, and for the same reason that population differences are anathema. Such differences, so the thinking goes, would support either racism (on the part of populations) or sexism (on the part of males and females). But of course that thinking is false: we can accept evolved differences without turning them into social policy. And it’s of interest to many evolutionists, including me, to know the extent to which groups and sexes have evolved along divergent pathways.

Still, many feminists, liberals, sociologists, and cultural anthropologists deny any such divergence. Yes, men and women differ in body size, strength, and structure, but there are, so they say, no such differences in the brain and behavior. In all other traits, so the trope goes, men and women are equal. And given equal interests and talents, then the only thing enforcing anything other than a 50% representation of men and women in professions must be cultural pressures: viz., sexism. Thus, unequal representation in professions is prima facie evidence of sex discrimination. But as Jon Haidt mentioned in the lecture I posted the other day (watch the video; it’s good!), one first has to determine the cause of such unequal representation before one decides what to do about it.

At any rate, in the humanities and especially cultural anthropology, which in its ideological slant really counts as (sloppy) humanities rather than science, these attitudes are not only religious in nature, lacking empirical substantiation, but are also theological in enforcement. Authors (as I’ve pointed out recently) assume what they want to prove, and then go ahead and collect just those data that support their hypothesis. Confirmation bias is rife. This is what theologians do, not scientists.

The paper I’m highlighting today (link and free download below) is by Charlotta Stern, associate professor and deputy chair of the sociology department at Stockholm University. She is a brave woman, for her paper aims at calling out those sociologists who simply refuse to consider biology as an explanation of sex-distinguishing behaviors. As she says, not pulling her punches:

The present investigation is informed by my long and ongoing experience as a sociologist at Stockholm University. My teaching and research often touch on gender issues. I have served on about five thesis committees that addressed gender sociology or related matters, and I have participated in dozens of seminars that touch on gender sociology. My relationships with my colleagues and students are not heated. When I raise ideas that would challenge the sacred beliefs, I do so only at the edges. I have seen how people react when I or another suggests that maybe there is a difference in math skills between men and women, or that men and women have different preferences and motivations. In my experience, gender sociologists frown upon such remarks about innate differences in aptitude or motivations. I perceive deep and widespread taboo and insularity among gender sociologists. It saddens me. I feel impelled to make available some expression of my concern, hoping that students and others will hear it before sinking into the sacred beliefs and sacred causes addressed here.

Her method was simple, and somewhat subjective. She examined a set of 23 highly-cited articles in sociology journals, all of which cite a classic paper in the field, “Doing gender,” by Candace West and Don Zimmerman (1987); reference and free link below).

West and Zimmer concluded (or decided in advance) that behavioral and non-physical differences between men and women were “constructed” based on their genitalia, so that all differences we observe in later life are the result of socialization. As Stern notes,

“Doing gender” is presented as part of a lamentable system of social control. The paper’s final para- graph reads:

“Gender is a powerful ideological device, which produces, reproduces, and legitimates the choices and limits that are predicated on sex category. An understanding of how gender is produced in social situations will afford clarification of the interactional scaffolding of social structure and the social control processes that sustain it. (West and Zimmerman 1987, 147).”

Stern examined 23 highly-cited sociology papers published between 2004 and 2014 (two per year) that themselves cited West and Zimmer’s influential paper. Then, developing a spreadsheet, she coded each of the articles as whether or not they took the hypothesis of biological differences between men and women as a serious possibility. Her classification was as follows:

Neutral. Discussions of gender differnces but no discussion of their biological bases, nor dismissal of them. (4 articles).

Blinkered. These are the articles in which, according to Stern, biological differences are relevant hypotheses, but are either ignored or dismissed out of hand (15 articles).

Unblinkered. Stern found only one article that considered biology as a possible explanation for sex differences in things like time spent with children, savings for education, and other “family processes.” Stern says the article has a “nuanced discussion of causality.”

Not rated. These articles “do not deal with matters for which biological difference ideas would clearly be relevant.” Four articles.

Here is Stern’s list of the articles and their ratings:

Now of course you can debate Stern’s methods and assessments, but what’s clear even without this analysis is that it’s taboo in much of academia to suggest that measurable differences between populations or sexes (excluding the most obvious physical differences) have any biological basis. But there should be no taboos in academics. One can debate the wisdom of investigating some questions (e.g., “Are Jews genetically acquisitive?”), but what one should not do is assume what’s true before investigating it. And, as Jon Haidt noted, if you don’t know the empirical basis for differences that are considered problematic (such as the underrepresentation of women in mathematics), you’re hampered from addressing them.

Stern’s conclusion is low key (my emphasis):

One cannot draw quantitative estimates on the basis of my investigation, but its findings are consistent with an image of gender sociology as a subfield that has insulated its sacred beliefs from important scientific challenges.

I have extensive first-hand experience with gender sociology’s insularity. But I also know of pervasive preference falsification (Kuran 1995), and I have seen students awaken with an ‘a-ha!’ moment when exposed to unorthodox thinkers such as Catherine Hakim (1995; 2000; 2008). I believe reform is possible. Whether people should ‘do gender’ less, and how they should ‘do gender,’ are questions worthy of personal reflection, scholarly exploration, and public discourse. More definite, to my mind, is that people should do less insularity.

charlotta-stern-300-214x300 — Charlotta Stern

h/t: Grania

____________

Stern, Charlotta. 2016. Undoing insularity: A small study of gender sociology’s big problem. Econ Journal Watch 13:452-466.

West, C. and D. H. Zimmerman. 1987. Doing gender. Gender and Society 1:32-57.

The evolutionary level of human violence

September 30, 2016 • 9:45 am

There’s a new paper in Nature about the level of intraspecific violence in humans and other species, written by José Maria Gómez et al. (free reference and download below). The question is how often members of single species kill each other in the wild, and whether humans are outliers. It’s already gotten a lot of attention in the press, including an Atlantic summary by Ed Yong, but I’ve avoided reading the journalism until I read the original paper. Now that I have, I’ll summarize the Nature paper briefly for those who haven’t seen other pieces about it.

First, the authors used data from the literature to estimate the level of lethal violence in 1024 species of mammals from 137 families. The question was this: what percentage of individuals who die within a species do so after interacting with members of their own species? That’s the measure the authors take as the degree of “lethal violence” within species. It does not include lethal violence from members of other species, like rabbits getting nicked by raptors.

When you impose that data on the known phylogeny (family tree) of mammals from genetic and morphological data, you can then, using techniques known for a while, estimate what degree of lethal violence existed in various species’ ancestors. As a hypothetical example, imagine a group of ten related birds, nine of which have crests and one of which was uncrested. Assume further that we know from genetic data that those birds all had a single common ancestor and were all each other’s closest relatives (i.e. they’re a “monophyletic group”). If that’s the case, then it’s a reasonable assumption that that common ancestor also had a crest. (It’s more parsimonious to assume that the crest was lost once than that it evolved nine or so times independently in the descendants of an uncrested bird.) That’s a simple example, but you can use techniques like that to make quantitative estimates, too, and that’s what the authors did for lethal violence.

They first imposed measured levels of lethal violence on the known phylogeny of mammal species. Here it is; the caption comes from the paper, and the color in a branch indicates the estimated level of violence in that branch, ranging from light yellow (peaceful) to dark red (violent). Click to enlarge, and notice the redness around carnivores and, especially, primates; more on that later:

nature19758-f1 — Tree showing the phylogenetic estimation of the level of lethal aggression in mammals (n = 1,024 species) using stochastic mapping. Lethal aggression increases with the intensity of the colour, from yellow to dark red. Light grey indicates the absence of lethal aggression. Mammalian ancestral nodes compared with human lethal violence are shown in red, whereas main placental lineages are marked with black nodes. The red triangle indicates the phylogenetic position of humans.

The authors also found that related species tended to have related levels of violence. That’s what I would have expected, and when I read that sentence I thought, “Well of course: violence is more common in species that are more territorial as well as those that are more social, for territoriality and sociality breeds inter- and intragroup competition for mates, food, and territory. And of course if a species is social or territorial, its relatives are likely to be social and territorial.”

And, sure enough, there was a strong correlation between both sociality, territoriality, and violence among the species. Here’s a graph showing that, with territoriality seemingly inciting more violence than sociality:

nature19758-f2 — (From paper): The figure shows the phylogenetically corrected level of lethal aggression per group (mean ± s.e.m) and the number of mammalian species included in each group. We used a phylogenetic generalized linear model (PGLS) to test the effect of territoriality (yes or no) and social behaviour (social or solitary) on lethal aggression. The level of lethal aggression was more intense in social and territorial species (PGLS, P < 0.05 in all cases and mammal phylogenies; Extended Data Table 1), with no interaction between these two terms (Extended Data Table 1).

Now what about our own lineage? Information about lethality was obtained from 600 human populations dating from the Paleolithic to the present, using both fossil (bone) and historical evidence. Lethal violence included homicide, cannibalism, war, infanticide, execution, and so on. Information was also available from H. neanderthalensis. There are two main results:

The proportion of individuals in the genus Homo killed by lethal violence was about 2%, and this estimate is robust to things like the uncertainty of phylogenies. This is pretty high compared to some other animals (see below), but is explained by the fact that hominins are both social and territorial. This is the ancestral condition before we became civilized. These levels persist in many non-“civilized” groups, though, and from this the authors conclude that there is an evolved, genetically-based propensity for humans to be violent at a level that causes roughly 1 in 50 humans to be killed violently by other humans. That baseline level can be reduced by the imposition of law and “civilized” societies.

Violence is correlated with human social organization. The authors divided human groups into four types: “bands” (hunter-gatherers and the like), “tribes” (small groups that live in semipermanent places, with egalitarian societies composed of hunter/horticulturalists), “chiefdoms” (hierarchical non-industrial societies pervaded by kinship ties), and “states” (“politically organized complex societies”). Here are the data, which show that “historic” bands and tribes didn’t differ significantly from the phylogenetic “ancestral” level of violence, while historic chiefdoms and contemporary bands and tribes have significantly higher levels of violence than presumed in our ancestors. In contrast, both historic and contemporary states have considerably lower levels of violence than the ancestral estimate, probably (as the authors note) because in such societies the state takes over the imposition of violence. That, in fact, is one of Steve Pinker’s hypotheses in Better Angels for the historical decline in violence over the last five centuries.

screen-shot-2016-09-30-at-9-04-07-am — Human lethal violence in different socio-political organizations28. In all cases the boxplots show median values, 50th percentile values (box outline), 95th percentile values (whiskers), and outlier values (circles). We tested whether the level of lethal violence observed in each ancestral node, human period and human socio-political organization differed significantly from the phylogenetic inferences in a.

Finally, I still haven’t read Ed Yong’s piece, though I will now, but I will reproduce a figure from his piece that someone put on Twi**er. It shows the level in violence among many species, and you’ll be surprised at the most violent:

Yes, the primates are up there, but Jebus, the most violent species is the MEERKAT, with over 19% of individuals killed by other meerkats. Who knew?

__________

Gómez, J. M., M. Verdú, A. González-Megías, and M. Méndez. 2016. The phylogenetic roots of human lethal violence. Nature, doi:10.1038/nature19758, Published online, 28 September 2016.

Slate author suggests that we stop idolizing chimps and model our society on bonobos

September 16, 2016 • 1:08 pm

When someone sent me the title of this Slate piece, “Why do we idolize chimps when we could be imitating feminist bonobos?“, I was sure it was a parody—perhaps from The Onion.

But no, I don’t think so—or else it’s parody that isn’t good because it’s so close to seeming real without a hint that it’s farcical. The author, Christina Cauterucci, was also a PuffHo editor (surprise!), and I can’t find any evidence of a scientific background.

At any rate, most of us know two things. First, chimps and bonobos, the latter now regarded as a species distinct from the common chimpanzee (former P. paniscus, latter P. troglodytes) are our closest living relatives. They’re equally closely related to humans, with our joint common ancestor living about 6 million years ago. The two chimp diverged from their own common ancestor about 2.4 million years ago.

Second, the social systems of the two chimps—bonobos were formerly called “pygmy chimps”—are quite different, with bonobos having a greater diversity of sexual behavior, more female/female bonding, and a pervasive use of sexuality as social glue. (Some have argued that in the wild, rather than in zoos or enclosures, the difference between the species is not as great, but let’s accept it for the time being.)

Another fact: we have no idea, given this divergence, what the behavior of the chimps’ common ancestor was like, nor, of course, do we have behavioral information about our own common ancestor with the chimps. Sadly, though, people have drawn moral lessons from chimps, saying that we should be more “bonobish” than “chimpish”, although there’s nothing in the evolutionary tree—or in science itself—that suggests such an “ought”. If we want to change our behaviors, it’s just dumb to try to find animal models and then say, “We should be like them.” What’s the point?

Yet that is exactly what Cauterucci does in her piece. She has a feminist ideology that she wants to see accepted in modern society (and I don’t disagree with her), but then projects it onto the bonobos, seeing them as “true feminists”, and then reverse-engineers this projection back onto humans as an “ought.” But there’s no need to draw any moral lessons from primates, even from our closest relatives. If we want to promote women’s equality, we can do it by applying rational arguments and empathy to modern human society, with no need to look to other species as models.

But Cauterucci can’t resist, and goes to ludicrous lengths to promote bonobos, diss chimps, and even goes so far as to promote what I see as misandry in humans. But let’s look at what she wrote—the kind of stuff that made me think this was a parody.

Bonobos, the Central African apes known for their libertine sexual behavior, have taken the advice of Madeleine Albright to heart. “There’s a special place in hell for women who don’t help each other,” the former secretary of state has often said, most notably at a February Hillary Clinton rally to great public censure from female Bernie supporters. If she’s right, female bonobos have earned a plot of prime real estate in heaven: They regularly band together to put aggressive males in their place, going so far as to bite off penises or toes if need be, all in the name of sisterhood.

A recent New York Times piece chronicles the many bonobo behaviors we humans should try to emulate, and they make women’s self-defense classes sound like Beanie Baby tea parties. In what might be the best anecdotal lede in Times history, four male bonobos “display their erections,” excited by the “exceptionally pink and swollen” rump of a fertile female, while catcalling her and rattling the branches on her tree. Three older, more senior female bonobos descend on the lecherous males; together, the four females manage to capture one of them. “He was healthy, muscular and about 18 pounds heavier than any of his captors,” the Times recounts. “But no matter. The females bit into him as he howled and struggled to pull free.” He eventually escaped, but didn’t come back to his bonobo community for weeks. Upon his return, missing the tip of one of his toes, he avoided his peers.

Take away the toe-biting (maybe), and this is exactly how human women could and should deal with rapists, abusers, and serial sexual harassers: Scare them away by any means necessary, expel them from the safety of an enabling social system, and ostracize them until they prove themselves reborn as humbled feminists.

“Take away the toe-biting (maybe)??” It’s indeed possible that male bonobo’s sexual behavior has common roots with that of human males, but we needn’t construct societal oughts from the way that females behave. I, for one, think that biting off the fingers and penises of catcallers is a bit extreme. And can we really see randy bonobo males as the primate equivalent of “rapists, abusers, and serial sexual harassers”? If you’re willing to say that, then you’re going the route of evolutionary psychology, but adding a veneer of human morality to it. Think about how you’d characterize male ducks or fruit flies! For ducks certainly have a “rape culture” more violent than do chimps.

In fact, humans have police, laws, and courts to deal with this behavior, so we needn’t resort to penis- and toe-biting. In that difference lies much of Cauterucci’s fallacious analogy.

Then comes the chimp-dissing:

The sad thing is that bonobos are equally close relatives to humans as chimpanzees, but we look to the latter far more often for clues about the roots of our species. Bonobos are light-years ahead of chimps in their sexual evolution. [JAC: this is completely bogus: one species isn’t “more evolved” than another. That kind of hierarchy was debunked a century ago. Each species is evolutionarily adapted to their environment] As the Times notes, they kiss with tongue, give one another oral pleasure, have sex while facing each other, and use their opposable thumbs for what our maker intended: making sex toys. Chimps just poke boring old sticks into termite mounds. They also have far stronger bonds between males than between females (the opposite of bonobos), kill their babies with relative frequency (bonobos never do that), and make females mate with every single eligible male (unlike bonobos, who practice some ape-like form of affirmative consent).

So why have we chosen chimps as our nearest and dearest genetic relatives? Seems like the evil machinations of a patriarchal, sex-negative, infanticidal rape culture to me. Of course, bonobos do condone adults having sex with bonobo children, a behavior humans have rightly discouraged. But chimpanzees are murderous aggressors. No species is perfect.

That second sentence sounds like pure parody, but I don’t think it is. I wonder what Jane Goodall would have to say about it. But seriously, no biologist now looks to chimps rather than to bonobos to trace the roots of our species. Historically, the common chimp was the subject for such work (Goodall being the most important researcher); but since we realized that there were two species of chimps with divergent social systems, nobody I know favors one above the other as the “evolutionarily accurate” wellsprings of our behavior.

As for dragging patriarchy, sex-negativity, and “rape culture” into animals, well, that’s pure anthropomorphism. And I point out again that either Cauterucci is just seeing cultural analogies here without any genetic basis, in which case there’s nothing to learn about the roots of human behavior, or she’s seeing genetically based similarities in behavior, in which case she’s adumbrating a form of evolutionary psychology—evolutionary differences between human males and females—that Leftist feminists often reject. (I myself think that a fair amount of modern human behavior—particularly sexual behavior—does have evolutionary roots, but I also think that we can transcend our biological heritage when it’s inimical to modern society.) Her suggestion that bonobos are “light-years ahead of chimps in their sexual evolution” suggests that Cauterucci does see a genetic basis in their divergent behaviors.

At any rate, Cauterucci is wrong to say that chimps are our modern paradigm of behavior, that they are “idolized” above bonobos, and that we should model our society on bonobos. Yes, of course women deserve to be free from harassment, and treated as legal and moral equals to males, but do we need to look to bonobos to effect that? Bonobos don’t have any sense of intellectual feminism, which is a purely human concept. Cauterucci suggests, in fact, that their “feminism” is evolved and not chosen. At the end of the piece, in fact, one gets a sense that Cauterucci glories in the male-bashing of bonobos, which of course isn’t something that our species should indulge in, either:

A California primatologist told the Times that bonobos “should give hope to the human feminist movement.” I would argue that the trend toward ironic misandry in modern pop feminism indicates that we’re already halfway to bonobodom. Imagine what glee a high-ranking bonobo female would take in eating her daily helping of insect larvae from a mug labeled “male tears.”

I can’t see why bonobos should give any hope to feminism—any more than common chimp should give hope to the men’s rights movement. This is what you get when you have a toxic combination of an ideological agenda combined with an ignorance of biology. (That, by the way, accounts for the frequent dismissing of evolutionary psychology by the regressive left).

But maybe Cauterucci is just pulling a big Sokal-esque scam on us, and Slate has bought it. And perhaps I’ve just wasted my time. You tell me!

But if it is a parody, it’s deceived a lot of people who read it as real, and given them misleading messages about evolution and the naturalistic fallacy.

_58696059_pair — Sexual bonding in bonobo females (photo from BBC)

Why is red nail polish so popular?

July 2, 2016 • 5:00 pm

Walking to the store the other day, I found myself bored and unable to brain. Then a woman passed me wearing sandals (it’s summer up here, after all) and bright red toenail polish. That gave me something to do: I decided to count the colors on the feet of all the women who passed me until I got to the store and then to my place. The only criteria were that I had to pass the women on the sidewalk, going either way, and that their toes were exposed so I could see if they were wearing pollish and, if so, what color. Here’s the total out of 28 women surveyed:

19 red
3 no polish or colorless polish
6 other colors: 1 white, 1 green, 2 purple, 2 blue

This is exactly the kind of experiment the great Victorian polymath Francis Galton, Darwin’s half cousin, would have done. Besides his huge contributions to statistics, he was always conducting crazy little studies to satisfy his curiosity, including surveying the women from various cities of Britain to see which city’s women were the most beautiful (as I recall, he had a card that he’d secretly punch when he saw a woman). You can see the winning and losing cities here.

My conclusion: women favor red toenail polish over other colors—by a large margin. I’m sure that one would get the same result if one surveyed fingernail polish, which I didn’t do. And, of course, it hasn’t escaped my notice that red lipstick is by far the favorite among colors. One might be able to get similar results simply by tallying the various colors on sale at drugstores or the beauty counters of department stores.

When I told one of my women friends this result, she said that she herself would never bare her toes without colored polish, and it was invariably red. When I said, “Why red?”, she answered “Because I like it.”

Well, that’s the proximate explanation, but I want to know why they like it. There has to be some reason why red is the most popular color. One explanation, of course, is simply that it’s the most visible or striking color, and thus calls attention to the toes, fingers, and lips. But then, why red rather than orange or bright yellow?

Now I’m sure that evolutionary psychologists have dealt with this question, and I’m almost as sure that the answers are varied. I would bet, knowing nothing about this question, that the answers involve either invoking the colors of berries gleaned by our ancestors, or the resemblance between the red color of the polish and the color of a woman’s excited nether parts (well, they’re not really red). Support for the latter hypothesis comes from the notion that the redder a woman’s lips are, the more sexual she is.

As for me, I’m content to have done my little survey, confident that the results are pretty general, and I’ll leave it to the evolutionary psychologists to provide hypotheses. Maybe some of them would even be testable. Can we color the nails of female chimpanzees or baboons and see what happens?

I would, of course, particularly like to hear from women readers, either adding to the tally or explaining their choice of colors (or why they don’t use color).

My conversation with Gad Saad

April 11, 2016 • 10:30 am

On Gad Saad‘s new videocast, “The Saad Truth” on Larry King’s network (Ora.tv), I talked with the affable Lebanese/Canadian psychologist for about 75 minutes. The original video is here, but it’s also on YouTube, which I’ve embedded. As always, I can’t stand to watch it; maybe you can.

Saad, as I’ve noted before, is a really nice guy, and though he has strong feelings about stuff like free speech and unthinking critics of evolutionary psychology, he’s always very mild-mannered when he’s proselytizing. Gad’s the kind of guy you’d want to have a few beers with. He also writes a column at Psychology Today, Homo Consumericus.

Why do we holler when we’re hurt? My dubious evolutionary-psychology hypothesis

December 15, 2015 • 10:29 am

We’ve all noticed and experienced the phenomenon that when we’re hurt, we yell. When we stub our toe, hit our thumb with a hammer, or burn ourselves, we often let out a bloodcurdling scream. People who are pushed off buildings do it, too—at least in the movies.

Yet when we experience intense pleasure, we don’t let out such vociferous yells. Yes, some people make loud noises during orgasm, but you don’t scream when you drink a delicious wine, have a bite of a wonderful meal, see a great painting, or suddenly come across a beautiful landscape or sunset. In other words, yelling is asymmetrical with the nature of feeling: it comes with pain but not with pleasure. And we also yell when we’re startled: notice what kids do when someone jumps out behind a chair and says “boo”, or we suddenly spot a big tarantula close by.

I was wondering about all this after I recently stubbed my foot on a chair in the dark, and uttered a loud “OUCH.” And of course I began speculating whether this response might be evolutionary. I’m not an evolutionary psychologist, and I’ve been a critic of its more facile forms—including unsupported “adaptive story telling”—but it exercises my mind to devise evolutionary explanations for behaviors. What I’m about to suggest is thus largely tongue in cheek, but I proffer it nonetheless.

My hypothesis (which is mine): Humans yell when they’re hurt or surprised because they want to call attention to their plight in hopes that nearby humans could help them.

Before anybody calls me a rampant and unthinking adaptationist, let me add that I thought at first this might be a reasonable hypothesis, but upon reflection don’t think it’s very good. Here are some arguments against it:

Humans yell when there’s no hope for them, as when falling off cliffs or they’re alone. (But this, of course, could just be an automatic response from genes that say “yell when you’re in trouble, for sometimes it helps”).

Other animals that aren’t social yell when they’re hurt, as with squirrels or rabbits when caught by a predator. There’s no evolutionary advantage I can see to this—with the possible exception that uttering a loud cry might startle the predator and induce it to temporary loosen its hold, giving you a second chance to live and pass on your genes.

But animals that have no predators, like dogs, also yell when they’re hurt. Everybody’s seen a dog yelp when it’s hurt. But do elephants do something similar?

I’m sure readers can come up lots of other counterevidence.

These ideas make two predictions: social animals will make more noise than nonsocial relatives when they’re in trouble or in pain. Or, if screaming when caught is an adaptation to startle your predator (after all, lots of animals have physical adaptations to do this), then animals that are less susceptible to predators would make less noise.

In the end, it’s likely that, given the ubiquity of shrieking among animals that have voices, I think that yells of surprise or pain may simply be an epiphenomenon: a nonadaptive reaction that may somehow be a byproduct of our neural wiring. But still . . . .maybe there’s something to it.

What it goes to show, too, is that you can concoct an adaptive story for almost any behavior. And I’m pretty sure that someone has written about this before, though I’m just guessing.

Evolutionary psychology, sexual dimorphism, and ideology

November 26, 2014 • 8:41 am

(Note to non-biologists: “sexual dimorphsim” refers to any trait or behavior that differs between the sexes, like the ornamented tail of the male peacock, the brighter color of the male painted bunting—and of many birds—and the bower-building behavior of male but not female bowerbirds.)

There are some science-friendly folk (including atheists) who simply dismiss the entire field of evolutionary psychology in humans, saying that its theoretical foundations are weak or nonexistent. I’ve always replied that that claim is bunk, for its “theoretical foundations” are simply the claim that our brains and behaviors, like our bodies, show features reflecting evolution in our ancestors. While some evolutionary psychology studies are weak, and I’ve been a critic of them, the discipline as a whole is growing in rigor and should certainly not be dismissed in toto.

Those who still do, though, should answer this question:

Why are human males, on average, bigger and stronger than females?

This is true not only in our species, but in our three closest relatives: chimpanzees, orangutans, and gorillas, as well as in most primates (there are a few exceptions, like gibbons).

The most obvious answer is male-male competition: our male ancestors competed with each other for females, and bigger bodies made for more successful competitors. That size difference can be useful in both direct physical competition (as in mule deer!) or simply in dominance, like establishing territories, or even in showing you have “better genes”. (In fact, mate choice based on size may still operate in humans if females prefer bigger or taller males as opposed to smaller ones like me.) And if males competed for females, that reflects a difference between the sexes in reproductive strategy—that is, in behavior. Finally, if the physical result of this behavioral difference remains in our species, why would the behavioral difference itself not remain as well, with males competing for female attention? Various psychological and sociological studies in fact show this to be the case in modern humans.

The theoretical underpinnings of the behavioral difference have long been understood and supported with data: the difference in parental investment that usually makes males less discriminatory in choosing mates than are females (sperm is cheap; pregnancy and suckling expensive). The theory also makes substantiated predictions. One of them is this: in those species (both primate and nonprimate) in which males have a larger variation among individuals in reproductive success (i.e., those having “harems” versus those that are more monogamous), the species having more variation (more “polygynous”) should show a bigger size difference between males and females. For in those species in which a male can garner lots of females, leaving a lot of males as chaste bachelors, there will be stronger selection for males be larger. And that is what we find.

So those who dismiss evolutionary psychology wholesale must still explain why in every human society males are on average larger than females. (The answer probably doesn’t involve an ecological difference between the sexes in our ancestors, as such ecological differences don’t seem to exist in our closest primate relatives.) And if you admit that those differences in body size reflect ancient evolution, why do opponents of evo-psych claim that the differences in behavior that produced the physical dimorphism are no longer with us?

This is not to justify any sex differences in behavior as “right” or “moral.” That is the naturalistic fallacy. But the left-wing opposition to evolutionary psychology as a valid discipline in principle, especially when it involves differences in sexual behavior, seems to me based more on ideology than on biology. Ideologues cannot allow any possibility that males and females behave differently because of their evolution. Such people think that this would buttress the view that one sex would be “better” than the other.

But what evolved does not mean what’s right or what’s inevitable; and everybody with two neurons to rub together knows that. Humans may have evolved to be xenophobic and even violent towards members of “outgroups,” but we have the ability through culture and learning to overcome such a tendency. And, in fact, overcoming xenophobia happens to be both more useful and more ethical in a world of wide interactions between people and nations—interactions much different from those experienced by the small social groups of our African ancestors.

Biology is not ideology, but neither should ideology dictate biology.

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