Humans. How is it that you can herd 200 of them into an aeroplane without a riot erupting, while they also commit unspeakable atrocities such as torture, genocide, and war? Anthropologist Richard Wrangham calls it the goodness paradox. In this well-reasoned book, he surveys research from a range of disciplines to try and answer why humans show this odd combination of intense calm in normal social interactions and a ready willingness to kill under certain other circumstances.

Traditionally, this debate has been ruled by two extreme viewpoints: we are naturally nice but susceptible to corruption, or we are naturally evil but kept in check by the forces of civilization. Wrangham wants to boldly go where few have gone before and says: “this debate makes no sense to begin with, we are both”. Aggression, he says, comes in two major forms, each with their own biology and evolutionary history. He calls them reactive and proactive aggression throughout the book but explains we can also call them hot and cold, or impulsive and premeditated. It is the difference between lashing out in a fit of rage or deliberately planning a murder.

Wrangham starts off with what primatological research tells us about violence in ourselves and our closest relatives, something which he explored before in his book Demonic Males: Apes and the Origins of Human Violence. Anthropological research, furthermore, has shown the “peace at home” and “war abroad” dichotomy that characterises humans. Our levels of reactive aggression are low, while levels of proactive aggression are high.

The bulk of the book then goes into the question of why we are so tolerant. Wrangham’s argument runs something like this: Reduced aggressiveness is a hallmark of domesticated species. Taken together with other hallmarks, a convincing case can be made that we are a domesticated species. A self-domesticated species to be precise. How? Social control in the form of execution by groups of adult males drove a reduction in aggression. Sounds controversial? Let’s unpack this a bit more.

“Humans. How is it that you can herd 200 of them into an aeroplane without a riot erupting, while they also commit unspeakable atrocities?”

Tolerance is rare in nature but common in domesticated species. Wrangham discusses Belyaev’s classic work on silver foxes in Siberia at length (see How to Tame a Fox (and Build a Dog): Visionary Scientists and a Siberian Tale of Jump-Started Evolution, reviewed here). It has shown that selection against reactive aggression results in domestication and comes with a suite of morphological changes: shorter faces, smaller brains, floppy ears, and white patches of fur. As an aside, at the very end of this book, the authors referred to work done by Wrangham and others on the underlying mechanism. He picks up the baton here and shortly explains his research on migration of neural-crest cells (a kind of stem cell) during embryonic development and hormonal control exerted by the thyroid gland, and how these produce the observed changes in morphology.

Archaeological findings show the same kinds of changes in human fossils (yes, including, only recently, a reduction in brain size). Traditionally, scientists have tried to explain this by finding individual adaptive explanations for each of them. But, says Wrangham, they are more likely a byproduct of domestication (mildly ironic, if you ask me, as Wrangham has contributed to this discussion himself in the past; his book Catching Fire: How Cooking Made Us Human argued that cooking led to reduced jaw and tooth size).

The idea of modern humans as a domesticated species is not new and Wrangham shows how it has been around since Darwin and before. But who domesticated us? We did. This allows Wrangham to discuss primatological research on bonobos. Generally known as the peace-loving primates that solve every problem with sex, the question arises of how a tolerant species is not invaded by selfish, aggressive individuals. In bonobos, females form coalitions to punish bullying males.

“How is a tolerant species is not invaded by selfish, aggressive individuals? […] Wrangham says that in humans it is coalitions of males that kill other males.”

In what will probably be seen as the most controversial point the book makes, Wrangham says that in humans it is coalitions of males that kill other males. To support this assertion, he turns to the rich body of anthropological research on hunter-gatherer societies that shows capital punishment is universal. In subsequent chapters, he argues how it explains why we care so much about reputation and how morality came about. Vital in this model was the acquisition of language, which made possible both conspiratorial gossiping and the careful planning required for capital punishment.

This leaves the other form of aggression, the proactive one. You might see where Wrangham is going at this point in his book. The corollary of the proposed mechanism for reduced reactive violence is that of carefully planned proactive violence. So, as we evolved to become a more socially tolerant, more docile species, we simultaneously gained the capacity for organised violence.

The idea that war comes naturally to us is something that many people really do not like. Stephen Jay Gould did not. Nor do people like anthropologist Agustín Fuentes (see Race, Monogamy, and Other Lies They Told You: Busting Myths About Human Nature) or Bad Religion songwriter and zoologist Greg Graffin (see Population Wars: A New Perspective on Competition and Coexistence). Others see no problem with an evolutionary explanation (see recently e.g. War – What Is It Good for?: The Role of Conflict in Civilisation, from Primates to Robots and Why We Fight: The Cognitive Basis for War).

“The idea that war comes naturally to us is something that many people really do not like.”

The interesting thing is that most people do not necessarily disagree with the data, but consider this kind of interpretation taboo. “We cannot have scientists saying that violence and warfare are natural, that would induce fatalism and remove any inclination to try and prevent or reduce it”. To me, that reeks of political correctness, and Wrangham’s defence is both spirited and logical. Most primatologists discovering the violent nature of primates did not become fatalistic (see e.g. Goodall’s Reason for Hope: A Spiritual Journey). He is, furthermore, careful to stress that evolution is not destiny, nor should an evolutionary explanation be hijacked for political purposes (this has happened too often already). And war is costly. As Wrangham writes, and as e.g. Steven Pinker has documented in The Better Angels of our Nature: Why Violence Has Declined, it has a strong tendency to disappear when it does not pay. Being a US scientist, he is careful to reiterate in his afterword that just because he puts forward capital punishment as an evolutionary explanation, that does not mean he supports the death penalty.

I found The Goodness Paradox a well-written and convincing book-length argument that is bristling with many other interesting ideas I have not been able to touch upon here. Especially the idea of two kinds of violence with their own biology and evolutionary history is revelatory. No doubt it will cause much discussion and disagreements. I think it is a model for thoughtful and respectful writing that shows how to dig into a controversial topic, survey its history, give the various schools of thought a fair hearing, and explain your argument.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

The Goodness Paradox paperback, hardback, ebook or audio CD

Other recommended books mentioned in this review:

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