I Want Jeremy Yoder’s Money

In a recent blog post, U of M biology post-doc Jeremy Yoder takes a hatchet to my campaign to promote “Don’t Sleep With Mean People” as the new Golden Rule of sex. He dismisses the concept as “inane pseudo-scientific claptrap,” questions whether it’s a serious campaign or just an elaborate joke to teach evolution (it’s both), and concludes with some faint praise: “I know that Brinkman can do better than this.” Ironically, his example of my “better” work is the song “Performance, Feedback, Revision,” of which “Don’t Sleep With Mean People” is just a sub-category. Act like a jerk (performance), fail to get laid (feedback), act like less of a jerk (revision). I could respond by lobbying Yoder’s current sex partner(s) to put my slogan into practice, but I don’t know them, so I’ll settle for an old fashioned rebuttal.

Yoder starts his criticism accurately enough: “Brinkman thinks… that if everyone followed his advice, we could select meanness out of the human population over some unspecified period of time.” Of course I think that! As an aspiring evolutionary biologist, he should too. In fact, a similar experiment has already been done on another species: the silver fox. It took only fifty years of intense selective breeding to turn a vicious wild animal into a friendly domesticated one. Is Yoder actually arguing that it would be impossible to achieve this same effect with humans in principle, or just that it would be difficult (impractical, immoral, undesirable) in practice?

These questions hinge on two of Yoder’s main critiques: whether the trait in question, “meanness,” can be strictly defined, and whether or not it has a genetic basis. The first relies on a false distinction: either we all agree perfectly about the definition of “mean” or we all have a unique and arbitrary definition. The obvious alternative is that we can agree on most of the definition while disagreeing about a smaller sub-set of tricky cases, and that’s all we need for this purpose. Even if each person defines “mean” slightly differently, as long as there is some agreement (ie murder, torture, bullying, extortion, aggression, rape, coercion, etc), and as long as that consensus serves as a common benchmark for selection, and as long as the difference between “mean” and “nice” behaviour has some genetic basis, there will be an evolutionary effect.

Yoder complains that the evidence I posted for the genetic basis of meanness was insufficient, and he has a point. The current evidence for direct links between human genes and behavior is more suggestive than conclusive. But it’s very suggestive. I originally pointed to this study and more recently added a link to this one, both of which show a correlation between a specific gene and certain kinds of aggressive or hostile or rash behavior, ie the kinds of actions that either are mean or could easily get mean with a little escalation.

Another reason I think meanness is partially genetic is the work of evolutionary psychologists Martin Daly and Margo Wilson, which interprets violent crime and murder as adaptive responses to high stress, competitive, dangerous environments. Daly and Wilson’s research is too complex to fully summarize here, but if you’re interested, their argument is captured nicely by this article, and I do my best to describe it in the Rap Guide to Evolution and in my TEDxSMU talk.


A picture is worth a thousand words, so take a careful look at the homicide statistics for the city of Chicago (above), revealing the number of murders committed by both sexes at each stage of life. If the forms of meanness shown in this graph aren’t at least partially caused by evolutionary adaptations, then why are they so much more likely to be perpetrated by young men than young women, starting at exactly the age of puberty, escalating until the average age of parenthood, and then declining until death? How could “culture” possibly explain that pattern completely, when the same trend can be found cross-culturally around the world?

Yoder dismisses (my presentation of) the Daly and Wilson research at the 2012 Ottawa Evolution conference with a sneer: “[Brinkman] had the chutzpah to tell a ballroom full of evolutionary biologists that teenage male aggression must be an adaptation because teenage boys are aggressive. Dude’s not big on the rigorous evolutionary hypothesis testing.” It’s hard to tell whether he objects to the original hypothesis or if he just didn’t follow my summary of it, but either way his statement is a proud display of ignorance.

Given the recent evidence that Genghis Khan has 14 million living descendants, the idea that we have evolutionary instincts for instigating violence shouldn’t come as a huge surprise, but neither should the idea that we have competing instincts for avoiding and deterring violence. It’s possible for these opposing instincts to coexist in the same species and be flexibly deployed in response to different environmental triggers, and this is where “Don’t Sleep With Mean People” works on multiple fronts. The more it catches on, the more it will condition the (social) environment to foster kindness and altruism, because sexual ostracism is a powerful motivator. And as a secondary function, it might also reduce the frequency of mean genes over time. As Rob Brooks points out in his recent blog about the #FreeDohar craze, these instincts run deep and won’t be easy to overcome, but sexual choice seems like a good place to start.

Yoder’s attack blog also complains that my campaign is “heteronormative as all hell” which of course is true of the genetic component only. The only sex that leads to reproduction is heterosexual, but the cultural impact of “Don’t Sleep With Mean People” is equally available to gay men like Yoder. This perceived (but imaginary) insult may have done more to provoke his vitriol than the actual scientific basis of my campaign.

In the end, Yoder’s critique finishes with an interesting twist: “Confidential to BB: Come back with a project that actually teaches people about how evolution works, and I’ll chip right in.” Now we’re getting somewhere! I’ve tried to make it clear that “Don’t Sleep With Mean People” is that project, the perfect conversation starter and thought experiment for exploring the implications of mate choice, sexual selection, courtship strategies, phenotypic plasticity, artificial selection, human evolutionary history, behavioural genetics, gene/culture co-evolution, and many other key areas of the field, each of which will be explored in the short documentary film I intend to produce with the crowdfunded money.

I hope Yoder will do the honorable thing and cough up ten bucks. If he does, I might even interview him for the film.

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5 Responses to I Want Jeremy Yoder’s Money

  1. Helga Vierich says:

    You did a good job here. Your explanation and reasoning is clear. All behaviour is ultimately biological and evolved. In humans, evolutionary drivers have been more about social than physical environments. But there is a problem with saying that you want to eliminate violence as if there was one gene for it. What worries me about the Silver Foxes experiment is two-fold.

    1) flight-fight responses in a predator like a fox are considerably less nuanced than in a social primate like a human. In humans, these strong responses function in multiple ways, beyond inducing violence or a speedy departure. It is adrenaline that fuels the courage to stand up to a bully, or to man a barricade and protest injustice. It is anger at unfairness and cruelty that makes people willing to confront incredible odds to change laws or overthrow corrupt regimes. I think we need our ability to feel outrage, courage, and defiance. Perhaps, occasionally, it is quite useful to have some strong emotional clue that it is time, now, to panic and even to do something desperate, like run out and push that baby carriage out of the way of the train.

    2) Humans have a prefrontal cortex. It major function appears to be inhibitory… it stops us from acting too impulsively, even under the onslaught of intense emotions. Evolution has obviously been pretty draconian about getting this latest add-on installed.

    It may be one of the reasons why our childhood is so extended – for this part of our brain does not even fully come “on-line” until our mid-twenties (and in some, it seems, even later…), and why humans everywhere in the world, no matter if they are foragers or industrial tycoons, tend to have a similar species-sepcific life span, longer by 25-30 years, than any other great ape. It has been subject to considerable speculation, but one of the reasons for this seems to likely to be that older folks have some distilled wisdom to offer the youngsters, in addition to the substantive support they provide in provisioning and baby-sitting for grandchildren. It might even help to explain menopause, which humans share with only a few other mammals, great whales among them.

    That prefrontal cortex might also do even more – it might be the way that natural selection was already making sure that you didn’t often sleep with mean people. See, meanness is not quite the same as the ability to get angry. It is something much more chilling. It is the enjoyment of suffering in another. It is often the creation of that suffering deliberately in order to find that twisty version of pleasure.

    Cruelty is but a distant cousin of anger. It is the difference between torture and a punch thrown in rage. It cannot be forgiven, whereas we have all, from childhood, been made to shake and say sorry to the best pal we just gave a black eye to… and in some cases, they were our best man at our wedding twenty years later, (or, in my case, my maid of honour).

    War and genocide, torture and “cold-blooded” murder, bullying, and “ganging up” on some new kid are all of a kind… they are from the book of hate and cruelty, NOT the book of fear and rage.

    It is fitting that you made your campaign about “mean people” — because ’tis clear enough that it is the book of hate and cruelty you want to edit. Go softly, my friend, for the nature of the cognitive system you are aiming for is not the same as in the foxes. Foxes are not cruel.

  2. Pingback: Baba Brinkman says he wants my money « Nothing in Biology Makes Sense!

  3. I think it may be possible to do that, but not with a free society. Choosing your partner won´t cut it.
    A lot of people qould not get partners or it would be a very slow thing.

    Also: Women like bad boys, status and power in men. It isn´t easy to undo the fruits of sexual selection .

  4. Mike says:

    Women are turned on by ‘meanness’.

  5. Pingback: A week of links - Evolving Economics

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