Wild beast within

What was the driving force that made us human, akin to but separate from other apes and our evolutionary cousins such as the Neanderthals? In The Goodness Paradox, the anthropologist Richard Wrangham approvingly quotes Frederick the Great in pointing to “the wild beast” within each man: our nature, he argues, is rooted in an animal violence that morphed over time to become uniquely human. When male human ancestors began to plot together to execute aggressive men in their communities, indeed to carry out such killings through what Wrangham calls “coalitionary proactive aggression”, they were launched towards full humanity.

Proactive aggression is premeditated, a feature that sets it apart from reactive aggression, which is impulsive, a response to some immediate threat. Hot emotion drives reactive aggression: someone insults you and you respond with a swing at their jaw. Proactive aggression, by contrast, is “coolly planned”: you are cuckolded, and for weeks you plan a revenge murder.

When the plotting inherent in proactive aggression unfolds in a group context, it becomes coalitionary proactive aggression. This practice depends on language, and thus remains beyond the capacities of the chimpanzees Wrangham has studied for decades in Tanzania and Uganda. When chimpanzee males brutally kill males of other communities during tense patrols, they gang up as a band of friends, following a simple rule: “side with your friends against the enemy”. What they do not do (because they lack a way of doing so, in Wrangham’s view) is confer and decide to target a specific rival within their own community.

Domestication syndrome

At some point after the evolutionary split from the non-human ape lineage – probably around 300,000 years ago, Wrangham thinks – our male ancestors began to do what the chimpanzees could not: plot together to execute aggressive males in their own social groups. How do we know this? Because we see evidence of “the domestication syndrome” under way in our ancestors at this time, indicating that they were becoming less in thrall to reactive aggression.

Wrangham unpacks the domestication syndrome by reviewing the famous experiments of the Soviet geneticist Dmitri Belyaev with silver foxes, intentionally bred for docility beginning in 1959. Over the generations, as these foxes evolved from snappish animals into puppy-like tail-waggers who approached and licked the researchers, they also developed a suite of characteristics that had no adaptive significance – such as floppy ears and certain coat-colour patterns. For Wrangham, this and other evidence from animal domestication points to a key conclusion: when a species has recently undergone a reduction in reactive aggression, embodied clues are left behind.

During human evolution, of course, no other more dominant species controlled the process: instead, we domesticated ourselves by eliminating the most aggressive males in our social groups. Our bodies did signal what was happening. Around 315,000 years ago, for example, “the first glimmerings of the smaller face and reduced brow ridge [compared to earlier human ancestors] that signal the evolution of Homo sapiens” began to show up. Sex differences in the skeleton soon began to diminish. Our species was set apart from all other human-like ones, including the Neanderthals, who did not self-domesticate. An animal analogy works, says Wrangham: if we turned out to be the more docile dogs, the Neanderthals remained the wilder wolves.

From this point forward in Homo sapiens there unfolded a fantastic cascade of cognitive and behavioural changes. The threat of being targeted for execution within a community explains a good deal of our human psychology, says Wrangham. As males co-operated to root out male bullies who were prone to reactive aggression, social standards of right and wrong took hold. People began to be concerned about their own reputation and that of others, and to exhibit “more prosocial, or more generous” behaviours than other primates. Moral responses evolved as inherently self-protective, because males could at any moment be plotting to kill you: “when the risk of being a nonconformist is that you will be executed, it is easy to imagine intense selection in favor of moral sensibilities that maintain you as part of the in-group”. In sum, we became human because of “our rough past” and “our cruel ancestors”. “Ironically,” Wrangham concludes, “executioners seem to have brought us to the beginning of wisdom.”

Biological determinist

He is quite evidently concerned that his execution hypothesis may be mistaken as approval for modern-day capital punishment. It is nothing of the sort, he explains, making the point that “judicial execution is an outmoded punishment that should no longer have a place in the world”, because it is both ineffective and often unjust. Of equal worry to Wrangham is that he may be read as a biological determinist. So he repeatedly inserts statements into the narrative to reassure his readers: he doesn’t think that just because violence is inherently part of our biology, and adaptive, it is inevitable. “Abundant evidence shows”, he writes, “that violence is socially influenced and socially preventable.” Humans are often astoundingly kind, he asserts further on, and “from an evolutionary perspective, the human rate of physical aggression within social communities is already strikingly low”.

Yet what then of that “wild beast within”? While the statements about social change and the malleability of human aggression are there, they are overrun by statements about the primacy of biology. Consider the D word, right there prominently on page six: “The potential for good and evil occurs in every individual. Our biology determines the contradictory aspects of our personalities, and society modifies both tendencies”. The word “determines” at the very start of the book is there for a reason: Wrangham puts biology in charge. Sometimes he takes this principle to lengths that seem far-fetched.

Did you know that “broader-faced men” who play professional hockey spend more minutes in the penalty box than do their counterparts with narrow faces? Wrangham duly notes that facial breadth is correlated with a propensity for reactive aggression. So then, if it’s just a correlation – not a causation – what meaning does the penalty-box comparison for hockey players carry? Who knows?

-Times Literary Supplement