Evolutionary Psychology and War: Are We Chimps, Bonobos, or Something Else?

Is war, in some sense, natural?

Here’s an example of a recent book (reviewed by the Washington Post) that makes the argument that it is:


And here’s the book at Amazon:


And, of course, there is always Desmond Morris’s “The Naked Ape.” It is probably the first post-World War II book of the “human war and aggression is natural” genre.

And here’s a historian’s perspective on the earliest debates on the issue (prior to WWI):


I find something distinctly fishy in the “war is natural” argument that I can’t quite put my finger on. I notice, for example, in the Washington Post review of “Sex and War”, the following observation:

“Sex and War” is an important effort to raise our species’ consciousness of its ugliest behaviors. Yet there are problems with its argument. The authors know that bonobos, as near to us genetically as chimps, have no such aggressive pattern, but they don’t explain why they focused on chimps instead.

If humans are as near, genetically, to bonobos as we are to chimps, then how are we to decide whether it is more “natural” to act like peaceful hippie bonobos or aggressive chimps?

About Santi Tafarella

I teach writing and literature at Antelope Valley College in California.
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4 Responses to Evolutionary Psychology and War: Are We Chimps, Bonobos, or Something Else?

  1. Anthony C. Lopez says:

    hi there – just thought I’d comment on this post because I have an interest in these topics. I don’t know how well read you are in the area, but have you come across Richard Wrangham’s work, especially his book “Demonic Males”? He is a renowned primatologist and has studied individual and collective violence across various primate species. This book is a culmination of previous academic work he has done. If you’re interested in primate violence, he’s the guy to read, not necessarily Potts and Hayden, who, as far as I can tell, have no research history in warfare at all. But their book does seem like an interesting pop-sciencey read, for what it’s worth.

    Ultimately, whether we are “closer” to chimps or bonobos is not as important (in my opinion) as the selection pressures faced by humans *after* the chimp-hominid split. The environments to which we are adapted as homo-sapiens are in many important ways different than the ones faced by either chimps or bonobos. People often forget this fact when relying on these analogies to generate inferences about human nature.

    All of this is not to say anything at all about the question of whether “war is natural.” The word “natural” carries too far too much normative baggage to ever clarify anything about behavior. Most careful evolutionary psychologists are quite keen to avoid the naturalistic fallacy in their work.

    Apologies – I just noticed you have another blog on Wrangham’s latest book “Catching Fire.” So it appears you are aware of him. 🙂

  2. santitafarella says:


    Thanks for alerting me to Wrangham’s other book (Demonic Males). I’ll check that out. I just have heard of his food book.

    Here’s my question for you: What came first: the small jaw or the big brain?

    In other words, did our big brains require that the jaw muscles overhanging the cranium get out of the way, or did the small jawing food cookers inadvertantly make way for faster brain growth? Or did the two phenomena coincidentally feed on one another? Put still another way: did our big brains drive us to cook food (so we could still actually chew it)—or did our small-jawing-cooked-food-sharing force our brains to grow for purposes of more sophisticated sociality?


  3. Anthony C. Lopez says:

    With respect to your important question, I would like to politely suggest that these types of “which came first” questions often miss the whole point of how natural selection works. It was no “coincidence” that jaw size and brain size evolved in tandem and in response to important socio-ecological pressures. Here I use “coincidence” in the sense of: “What a coincidence – we haven’t seen each other in 10 years and today we just happen to walk into the same bagel store!” However, it IS the case (in my opinion) that the two phenomena to which you refer “co-incidentally” fed upon each other. I suspect this is what you had in mind. Natural selection is a feedback mechanism, in which changes in one part of the system can have repercussions for all other parts of the system, however distal they may be. In other words, changes in one adaptation have consequences for the structure of other adaptations in a never-ending process of reciprocal micro-adjustments. A particular adaptation is not just molded in response to what one would conventionally imagine as the organism’s “external” environment. More precisely, the “environment” – with respect to the adaptation – consists not only of elements external to the organism (food, predators, etc.) but also of elements internal to the organism (other adaptations, such as brain size, gut size, etc.).

    So natural selection is a continuous feedback process whereby fitness trade-offs are constantly managed throughout all aspects of the phenotype, and in which the ultimate currency is genetic fitness.

    Cooking (according to Wrangham) was not the only factor driving larger brain size; other important pressures were significant as well, such as group size (see Robin Dunbar’s work), distribution of resources, social structures, etc. Of course no one can study everything at once, so as scientists we must isolate what we perceive to be important selection pressures, generate hypotheses about adaptation structure given putative selection pressures, and run tests to see if we are correct. But when we are correct, as I believe Wrangham is, this is not to say that the selection pressures we have modeled are the sole or even primary shapers of the adaptations we have studied. Just as no effect can have merely one cause, no complex adaptation is a product of merely one selection pressure.

    Great way of not answering your question, huh? 🙂 Bottom line, as I think we would both agree, is that the “which came first” question is almost always necessarily an ill-posed problem. Especially when natural selection is involved.

  4. santitafarella says:


    Thanks for the clarification. I completely agree with you. I suppose that, for purposes of simplification and narration, we look at what evolution did, and then we pick out the significant thing here or there that, in retrospect, proved most important (like jaw size related to brain size). Like Columbo, suddenly the cracked window (or lack of cranium fusion), otherwise unnoticed, takes on importance in solving the “crime.” All story-telling arrives as obituary (after the fact).

    I also think of James Burke’s “How the Universe Changed” series as providing examples of contingencies coming together in curious ways to change the course of history (but that could not be anticipated in advance of the events).


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