A Primatologist Looks at Gender

Frans de Waal, Dutch primatologist extraordinaire, has written a book that I found important enough to write a blog about. It’s titled Different: Gender Through the Eyes of a Primatologist.
 
        Calm Down...
 
And before you go all ape on me, let me say that Dr. de Waal does not justify human gender relations, nor does he think that things are fine as they are. He tells us upfront that the whole idea of one sex being mentally superior receives zero backing in modern science. Male supremacy is not a natural order among primates. In fact, he tells us, typical primate society is, at heart, a female kinship network run by older matriarchs. But, on the other hand, de Waal is not a proponent of neo-creationism either. He is clear that humans are subject to the laws of nature, and that evolution did not screech to a halt when humans arrived. Humans are animals, and—specifically—we are primates. Hence the relevance of studying and understanding primate behaviors.

De Waal’s disclaimers:  He is looking at human behavior that is related to primate behavior, and in doing that, he is going to look at the literature on human behavior. He does not trust self-reports, but prefers the studies of tested and observed actual behavior. Omissions, he warns, will include: economic disparity, household labor, access to education, and cultural rules for attire. Now, obviously, these are huge influencers in the ways that gender plays out in human societies, but they are not universal for other primates… hence the omission. And, yes, I still think his book is valuable.
 
So enough taxiing down the runway. Let’s get to it…
 
                                                   Nature or Nurture?
 
So, right out of the gate, “Is it nature or nurture?”
 
Many humans assume that we socialize our children via the toys we select for them. But de Waal comes to a different conclusion from studying young primates: Play cannot be dictated. Confronted with a pile of random toys, young female primates overwhelmingly prefer plush toys and young males are attracted to things with wheels. Given a toy train, a young female will swaddle it and carry it around like a baby. According to the author, there is “consistency in finding a sex difference in the preferences for toys typed to their gender,” and he concludes that “the strength of this phenomenon points to the likelihood of a biological origin.” Notice the extreme carefulness of the language here. He must know the same people I do.  One of the most dramatic differences is in the play itself. The males enjoy roughhousing, but the females do not. They enjoy a form of play that has a storyline. Because of this, the two sexes practice segregated play.

So, does this mean nature trumps nurture? De Waal answers the question with another question: “Is a percussive sound made by the drummer or the drum?” Obviously, the answer is “both,” because on their own neither makes the sound. One could say the environment “plays” on our genes, as it were. This is “interactionism,” which assumes a dynamic interplay between genes and environment. Interactionism is not popular, because it does not offer easy answers. I’m going to say that again: Interactionism is not popular, because it does not offer easy answers.
 
“Every human tendency, regardless of whether we rate it as natural, can be amplified, weakened or modified by culture. If the gallons of ink spilled on the biological basis of altruism, homosexuality, and intelligence has taught us anything, it’s that every human trait reflects an interplay between genes and environment.”
 
Okay, let’s take language.  Adopted babies will speak the language of their adoption… obviously a cultural/environmental phenomenon. On the other hand, human language faculty is unique among primates, and that uniqueness is biological. So… nature and nurture.
 
Another quick example:  The Pill. It changed the biology of females so radically, that the entire cultural playing field was and still is (I hope) permanently reshaped.

Here’s another useful term: “learning predisposition.” What that means is being programmed to learn certain things at a particular time in our life. Like the way baby ducklings imprint. At a young age, they learn to identify with the species to which their mother belongs and follow her around—an obvious plus for survival. But when the mother duck is absent, these ducklings can imprint on a human caregiver, or a dog, or a goose, which may be less adaptive, but does result in a plethora of adorable Youtube videos. 
 
By the way, primate infants are extremely vulnerable, and newborns will die within twenty-four hours without intensive caregiving. Yes, males could provide some of this caregiving, especially with older babies, and sometimes they do take on that role with orphaned chimps… but there is only one sex that is 100% guaranteed to be present at the time of birth: the female. (Because, duh, she’s having the baby. Also, human fathers are the only primates who understand the mechanics of biological fatherhood. The concept is lost on male chimps and bonobos.) Because of this, it’s an obvious choice on the part of evolution to equip females with built-in “learning predispositions” for caregiving. “No person currently walking the earth could have gotten here if it weren’t for ancestors who survived and reproduced. No exceptions. Otherwise, they wouldn’t be here. Their genes are not in the gene pool.” (Consider the offspring of a female with a genetic makeup completely lacking in maternal predispositions. Brilliant as she might be, her offspring are not likely to survive, and her brilliance dies with her… unless she can write for a species that can read.)
 
The author makes the point that human gender roles are subject to similar “learning predispositions,” but, at the same time, he notes, “Roles may not be biological, certainly in all their details, but they are culturally acquired with a speed, eagerness, and thoroughness that hints at a biologically driven process.” Interactionism. See, we can get through this.

We just looked at maternal caregiving.  What about other expressions of gender? Let’s look at neuroimaging studies. (“Neuroimaging” means producing images of the brain by noninvasive techniques. It enables studies of a living brain, as opposed to dissection.) So… neuroimaging studies of humans indicate that imitating people of one’s own sex activates reward centers in the brain. Primate science. Evolution equipped our young with a feel-good bias to conform to the gender associated with their sex. Why? Because in primate societies the roles for males and females are very different throughout their lives. We know from studies that male chimps and bonobos strive for status and territory. We know from studies that the female apes protect and nurture their young for years. (See above.) And we also know that ideology has nothing to do with it. We know this is about sex at birth. It’s about preservation of the gene pool, which means optimizing the chances for the offspring to survive. And primate babies, including humans, take a long time to grow up.
 
“Children self-socialize via selective attention, imitation, and participation in particular activities and modality of interaction.” In primate societies, for example, chimp daughters watch and learn how their mother’s extract termites (to eat). This is a sex-segregated skill related to their role as feeders and nurturers of their offspring. Likewise male chimp infants seek male models. At first glance, teaching and learning may appear to be purely cultural and not biological in origin, but let’s not forget those internal reward centers for same-sex imitation. Primates are wired to copy those with whom they bond and identify, i.e., the members of their sex. The drummer and the drum.

De Waal notes that most differences across the sexes are bimodal (either male or female) but differences between genders present across a spectrum. Our current culture has become deeply polarized around this issue. We either want to staple a rigid set of gender roles firmly to biological sex, which is overwhelmingly bimodal, or else we want to flow with the fluidity of gender and downplay biological sex altogether, declaring it to be irrelevant. We do this at our peril, because in patriarchy, this approach has disastrous consequences for females. The consequences of gender role enforcement are also disastrous. But this is what we do, because interactionism is hard.
 
Also, science hasn’t always been scientific. Like many of us, science has found interactionism too hard. It has tended to ignore sex differences for a long, long time. In other words, ignore women. Finally, mercifully, this is starting to change. This neglect has been catastrophic for women, from barbaric male-dictated birthing practices, to male-modeled crash test dummies, to failure to study the impact of medications and vaccines on women’s reproductive systems. Remember thalidomide and the courageous woman in the FDA who, at great risk to her career, insisted on fetal studies of the drug before she would license it? Turns out thalidomide was responsible for a nightmare array of birth defects, and the horror of it was that it was being prescribed specifically as a sleep sedative to pregnant women who were struggling with insomnia related to the pregnancy!

 Being a scientist, De Waal puts forward a theory about the science of transgender identity and behavior: “One speculation is that in a fraction of human pregnancies, the body takes off in a different direction than the brain. A fetus’ genitals differentiate into male and female during the first few months of pregnancy, whereas the brain differentiates by gender in the second half of pregnancy… Gender identities are probably shaped in the womb from hormonal exposure. Experience after birth seems to have little impact. This could explain why no amount of conversion therapy, combined with prayer and punishment, changes the minds of transgender persons… Not every human trait is malleable.”
 
Here, he is actually drawing on science. Human brains are not gender neutral. Again, nature or nurture?  Are our brains different because of hormones or experiences? Or both? Currently we don't know, but it’s a thoroughly established fact our brains are sexually dimorphic. What does that mean?  Sexual dimorphism is the “systematic difference in form between individuals of different sex in the same species.” Specifically, some parts of the male and female brain differ from each other in size or appearance. And before you accuse me of “neurosexism” or come at me about “lady brains,” there are more than 20,000 scientific articles documenting sex difference in human brains. Should it be unthinkable that this dimorphism might have some evolutionary connection?  I’m going to keep an open mind on the subject, and I found De Waal’s speculation interesting.

So what about homosexuality? The bonobos, as noted, are extremely sexually active, and their partnerings are often with members of the same sex. In fact, three quarters of bonobo sex could not result in procreation (same-sex, too old, or too young partners). Interestingly, the levels of oxytocin, the “love drug,” are higher in the urine of female bonobos after sex with another female. Enhanced oxytocin production has been seen as a hormone to facilitate childbirth, but possibly its bonding function in some primates is significant. (Footnote: As De Waal points out, there are no species other than humans that are truly "homosexual," as in exclusively attracted to members of one's own sex. And, yes, that includes those famous male penguins at the Central Park Zoo.)

What about the chimps?  Same-sex partnering among chimps was thought to be rare until recently. Today it is reported as frequent. What changed? Definitions and attitudes.  Today studies include sociosexual behavior, which is defined as “physical interaction involving contact with the anogenital region except for mating/copulations."  In the past, these behaviors had been dismissed as  “reassurance” or “reconciliation,” or “gestures.” Today they are acknowledged to be sexual.

Nature or nurture? The author explores the literature about brain studies exploring structural differences in the brains of gays and lesbians. He sites the work of Ivanka Savic and Per Lindström, who were studying human brain symmetry, which has no relationship to behavior, is fixed at birth, and is not altered by life experiences.  Their work indicates that sexual orientation may be forged in early infancy or even in the womb. But the primate culture of the great apes certainly doesn't discourge same-sex partnering.

                                         Violence Against Women
 
Much of de Waal’s focus is on primate violence in general, and, human violence against females in particular. Studies show that primates resolve conflicts, sympathize with each other, and seek cooperation. Both human children and primates demonstrate spontaneous altruism without enticements. Bonobos are taken as proof that violence is not hard-wired in, and most of the time both chimps and bonobos live in harmony. That actually goes for humans, also. Philosopher Mary Midgeley, who wrote about the relations of humans and animals, notes that humans are ultra-social, with communal values, even though we have a body of literature by men and for men depicting us as greedy individualists with only a veneer of goodness.  Propaganda?
 
There are no confirmed reports of bonobos killing each other, but there are many cases where chimps have ganged up and murdered male members of their tribe, sometimes brutally. Remember, the bonobos are sexy, peaceful, and female dominant. Male chimps also commit infanticide, and female chimps copulate widely to ensure protection of the young. Yes, these females have sex for excitement, attraction, adventure, and pleasure, but always behind it lies the threat of infanticide. If a male is bonded with the female through sex, he is less likely to murder her baby. (Again, he has no notion of fatherhood.) And, sadly, we have to include humans as among the species that commit infanticide. (Others include lions, dolphins, bears, prairie dogs, and owls. I know… dolphins?) Our infanticide? Step-fathers murder step-children with more frequency than the biological fathers. War is a large-scale scenario where the older father figures routinely send out the younger males to kill other younger males and to be killed. Why? Less competition for these aging males.
 
Female chimps receive more favors when they are in estrus, which is marked by highly visibile swelling of their genitalia. They barter sex for favors. The female bonobos, on the other hand, never threatened with infanticide or male violence, simply claim what they want, which happens to be an enormous amount of sex… with both males and females.

The author notes that female sexuality among both species is as proactive and enterprising as that of the males… but for different evolutionary reasons. And here is a fascinating side note about the bonobos:  During sex, the male will stop thrusting and dismount  if the female is avoiding eye contact or signals boredom by yawning or grooming. The bonobos demonstrate a clear grasp of the female’s right to change her mind. Sigh.

Which takes us back to the subject of human male violence against females: “If there is one aspect of social life that is gender-biased, it is physical violence. Males are its overwhelming source, and it applies equally to most other primates.” Statistics show that 22.1% of women and 7.4% of men have been victims of male violence. 13.5% of all human homicides are male-perpetrated, sex-based hate crimes against women. HOWEVER, these stats don’t take into account the massively under-reported incidence of “domestic violence.” With this epidemic murder of females, humans really stand out from other primates, even the chimps. 

Chimps do physically abuse and harass females, but they do not rape or murder them . And, of course, the male bonobos learn early that they will get the you-know-what slapped out of them by the adult females if they even THINK about messing with them. Also, the bonobo females travel together and sleep within earshot of each other, both of which are huge curbs to male violence. Groups of both bonobos and chimps are sex-segregated: “Males and females dwell in different worlds, each with its own set of issues.” Among primates, males compete with males and the females compete with females. (Among the chimps, the male bonding is stronger and they prefer it.) The sexes only meet occasionally and mating is done in the open, where others can interfere.
 
On the other hand, humans integrate the sexes into a single framework… often the “nuclear home.”  This arrangement facilitates male control and abuse. (This level of sex integration is relatively recent, having intensified during the Industrial Age.) The author reminds us that during COVID, where people were compelled to isolate within their homes, reports of domestic violence tripled.

So, rape.  Male orangutangs rape, and so do male ducks. Oh, and male scorpion flies. And then, of course, human males. What percentage of men are rapists?  Speculation varies… 1 in 5? 1 in 10? 1 in 20?  The frequency and prevalence of rape are staggering in our species. Some will say that rape is an evolutionary “adaptive strategy” to maximize fertilization, but if this is so, then why is it so extremely rare among all the species on earth? And it’s not “adaptive.” If it were, there would be no raping of girls, wives, post-menopausal women, or males. But here we are… Furthermore, tribal studies show an intolerance of the behavior, because in tribes there is physical proximity of kin, less female dependence on men, and less male bonding. Possibly, if chimps were forced out of tribes and into suburban cages with a lone female partner, they would begin to rape and murder females. Nature or environment?
 
But De Waal is careful to point out that biology is not irrelevant in considering violence against women. Sons, as he says, are not daughters. Sons will grow up more prone to violence. Sons will have more bodily strength.

Let’s take a sec with this, because it’s a huge part of the current gender controversies. Are human males stronger? So… “constitutional body strength.”  1% of women can lift 110 pounds directly off the ground. Two thirds of men can. Hand grip strength is another test that bypasses athletic training and fitness. 90% of young females fall short of 95% of men. Significant and documented difference.    
BECAUSE this is true, De Waal posits, we need to teach emotional skills and attitudes, and we need to offer healthy outlets for aggression. And, I would add, a good long look at alternate living arrangements that ensure safety for women and children.

                                                  How Primates Interact
 
Among chimps and bonobos, the males are pack animals, while the females prefer serial one-on-one friendship. The boys enjoy quarrels about rules, but quarreling ends the game for girls. They distance themselves from adversaries, while the males adopt a “nothing personal” attitude. In fact, male opponents actually seek each other out.
 
All social mammals practice reconciliation. Among chimps, 47% of the males reconcile. Only 18% of the females do. The males are opportunistic and keep their options open. Four out of five female conflicts go unreconciled. In sum, the males are good at making peace. The females are good at suppressing conflict. On the other hand, female bonobos don’t hold grudges and can actually make up in the middle of a fight. In conflict, two female chimps will be screaming in anguish. When male chimps fight, only one party screams—the loser.
 
Sadly, we resemble male-bonded apes more than the matricentric bonobos. Also sadly, primate dimorphism tends to stick in our subconscious. We respect height, muscularity, and low voices. (I’ve seen that in theatre for decades.) How can we change this? De Waal recommends an appreciation for the evolutionary roots of these biases, not a denial of them. Amen. Hence the blog.