A recent study of chimps in Uganda is being misinterpreted to suggest human murder is natural, and sloppy scientists are reenforcing these beliefs.
Chimps have long been known to be murderers and cannibals. While dominance within many species is often violent and considered essential for the social organization of many species, it very rarely extends to murder and except for chimps, to cannibalism.
So scientists have been at odds for years trying to explain this behavior in chimpanzees. Research came to a head about five years ago when scientists carefully documented chimp gangs that persistently (sometimes over ten years) plotted against one another then celebrated territorial victories by eating their foe’s babies.
Anthropology Professor Jill Pruetz believed for many years that this chimp behavior was aberrant, that it would not occur naturally in the wild were it not for some unnatural interference. Most of the colleagues who agreed with her believed that “something else” was human interference.
It could be chimps mocking human behavior (many chimp studies occur near very violent parts of Africa) or humans stressing chimp’s habitat, but it seemed just impossible to ascribe murder and cannibalism to natural behavior.
Pruetz and most of the scientific community have relented based on a just published study in Nature.
The “study says chimpanzees kill their own as a survival strategy, not due to human contact,” summarizes science journalist Monte Morin in yesterday’s L.A. Times.
And as far as I can tell, virtually everyone agrees.
That’s fine. But what’s not fine and in my opinion absolutely horrible is to use this study as an explanation for human violence.
Arizona State professor Joan Silk wrote an opinion article in that same issue of Nature, which she titled, “The evolutionary roots of lethal conflict,” which says it all.
A closer look at Silk’s opinion may be more nuanced than the title, but her title is what was picked up and replayed time and again in the less refined media. Clearly she committed a grievous scientific error in not adding “in chimpanzees” to her title.
There is absolutely nothing scientific or even rational to presume that behavior in chimps explains behavior in humans.
In what I feel is yellow science Silk invited the comparisons.
“The origins and prevalence of human warfare may be echoed in the search for the answer to chimpanzee adaptation,” wrote one scientific blogger yesterday, and it’s a wholly rational conclusion from Silk’s title, whether she intended it or not.
“Peace-loving anti-war activists call war ‘unnatural,’ but our closest animal relatives show that at least a little bloodshed is perfectly natural,” wrote Rebecca Kaplan in Tech Times, yesterday.
And on and on.
Studies of evolutionary behavior cannot extend back 6-10 million years to the separation of the hominin and ape branches of the hominid evolutionary tree. That’s just too long ago.
Behavior changes infinitely more rapidly than DNA. To claim that today’s chimp’s murder-and-cannibalism as a survival tool means that our earliest common ancestor with chimps had that behavior, too, is ludicrous.
And even if the ECA did, it’s impossible to suggest that our behavior today is still manifest by it.
There is no question that war has been used as a survival tool by humankind. But this is not because it’s ingrained in our genes, which is how the current chimp study is being distorted.
Why human violence evolved is certainly an interesting question, but it’s not biological. And what’s even more troubling is how the uneducated reaction to this study devolves from societies to individuals, suggesting all individuals carry a kill instinct.
I am so upset by this race to justify murder and violence. It slips so easily into the contemporary narratives supporting police using excessive force, violence and abuse against the less powerful like spouses and children, and not least of all, the rush back to war.
These are very troubling times, and scientists need to be very careful today. Joan Silk was not.
Long ago I did a little bit of molecular biology research. People in the “bench” (lab) sciences would often deride behavioral science and scientists because their scientific method was somewhat less than rigorous and therefore their conclusions often ridiculous. It seems that things have not changed.
Jim – According to The Christian Science Monitor report of the study, Jane Silk agrees with you regarding NOT looking to the findings of the study to account for human violence. She sees the violent behavior as “ingrained but not innate…a significant” distinction.
“The data tell us that there are some ecological and demographic circumstances in which the benefits of lethal aggression exceed the costs for chimpanzees, nothing more,” she [Jane Silk] writes. “Humans are not destined to be warlike because chimpanzees sometimes kill their neighbours.” Consider the possibility that Nature, not Silk, provided the title for her piece.
(When I tried to find the Monitor article again, since it showed up on Google news, I got The Times of India version instead. Evidently, as you may have discovered, the only thing the study in question establishes is that the aggressiveness of the chimps is NOT related to human destruction of habitat and has nothing to do with human war.)
Thank you so much for the comment, but I’m not quite so convinced that the magazine, rather than the author, controls the title. That isn’t my understanding at all, and one of the reasons science journals like Nature have sometimes such bothersome titles. It’s good to know, as I say in my blog, that the body of her article is more nuanced, but the intellectual infraction came in the title and that is the grievous error.