Humans
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The human capacity for violence is self-evident, but anthropologists are divided over whether our aggression is the product of nature or nurture. For instance, some argue that violence has deep evolutionary roots and is therefore a part of who we are, while others contend that it arose alongside cultural or socio-ecological phenomena such as the development of agriculture and state-level societies.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.Yet new research suggests that both may be partially true. Using data on incidences of mild and lethal aggression in 100 different primate species, scientists found that deadly conflict is much more common within this biological order than previously thought – but that aggression probably doesn’t exist as a single evolutionary trait.
Until now, it had been largely assumed that the tendency to kill rival adults was unique to humans and chimpanzees, yet the study authors found evidence for lethal violence in roughly 20 percent of primate species. “This shows that the potential to kill other conspecific adults is quite widespread and probably deeply rooted in our evolutionary past,” Professor Bonaventura Majolo from the University of Lincoln told IFLScience.
You cannot really characterize a species as being super aggressive or very un-aggressive.
Professor Bonaventura Majolo
However, Majolo and his colleagues also found that multiple types of aggressive behavior exist, and that they aren’t all evolutionarily linked. For instance, the researchers were surprised to observe that mild and deadly violence appear unconnected, as the species that commit the most frequent acts of low-level aggression are not the most likely to kill.
“From an evolutionary point of view, not all the different types of aggression or violence are strongly related to one another,” says Majolo. “And so you cannot really characterize a species as being super aggressive or very un-aggressive.”
Overall, the team’s findings show that the capacity for physical hostility is likely to be a common theme throughout the animal kingdom, but that the evolutionary mechanism behind this belligerence may be separate from that underlying the ability to intentionally kill. Moreover, despite the fact that humans are clearly capable of fatal attacks, such infringements remain highly dependent on culturally-patterned behaviors.
“Anthropological studies suggest that around 15 to 20 percent of small-scale hunter-gatherer societies don't wage war, and some don't even have a word for war,” says Majolo. “But that doesn't mean that these societies are completely peaceful,” he adds, as interpersonal violence may still occur within these groups.
The results of this study therefore highlight the complexity of aggressive behavior, underlining the futility of all conversations over whether humans are naturally programmed for violence. Moreover, as Majolo points out, “the argument that there is an evolutionary propensity to be aggressive under specific ecological or social conditions shouldn’t overlook the importance of free will.”
“So saying that violence is embedded in our evolutionary past doesn't mean that we are violent and there’s nothing we can do about it,” he adds.
For an example to follow, Majolo points to his study subjects. “Primates spend a considerable amount of time maintaining and establishing friendly social bonds with their group companions, grooming each other, engaging in behaviors like coalitionary support, tolerance, peacemaking and reconciliation when they have arguments or conflicts.”
Perhaps we should do more of the same.
The study is published in the journal Evolution Letters.
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