The Decline of Violence in Homo sapiens – The Human Evolution Weblog

[The following is highly condensed from my chapter The Decline of Violence in Spring/Nature’s new Encyclopedia of Evolutionary Psychological Science.]

Scanning the information headlines every day, we’re left with the impression that our world is a cesspool of battle and violence. The fact, nonetheless, is that our species is among the many most peaceable. Whereas Steven Pinker and others have concentrated totally on the pacification of human society from the daybreak of civilization to now, the roots of peace and concord run a lot deeper. In comparison with our fellow apes, human social teams are marked by elaborate cooperation, empathy, altruism, and nonviolent battle decision.

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Scientists have lengthy been concerned with what makes human so totally different from different animals and, relating to peaceable co-existence, now we have lastly begun to make progress. That is vital work as a result of, by understanding how we turned peaceable within the first place, we will achieve insights into why and the way we pursue reconciliation relatively than violence and, hopefully, we will construct an much more peaceable future.

There are not less than six main mechanisms which have contributed to the pacification of Homo sapiens as our species advanced over the past million years or so. Whereas some scientists quibble with a number of of those, all take pleasure in some measure of broad help amongst specialists on this subject.

Intelligence, Communication, and Language

I’ve usually written in regards to the spectacular language of different animals, from the precise “phrases” of monkeys and prairie canine to the gestures and different physique language of chimpanzees. However make no mistake, human language is orders of magnitude extra complicated than that of every other animal. Whereas some animals can consult with particular issues, use descriptors, and make calls for or requests, that appears to be as complicated as it will possibly get. Human language, alternatively, includes many components of speech, phrases with declension and a number of meanings, verbs with tense, temper, and situation, and so forth.

A number of traces of analysis have linked intelligence, language, and peaceable sociality. In primates, there’s a suggestive correlation between mind measurement and group measurement, indicating that the cognitive skills that make us distinctive are not all about bodily abilities, however social ones. Esther Herrman has crafted the “cultural intelligence speculation” to advance this concept. In comparison with violence, peaceable battle decision to violence requires way more social reminiscence, empathy, and understanding, in addition to refined communication and nuanced language.

Aggressive cooperation

Whereas competitors and cooperation may appear to be opposites, teams of animals, together with people, usually group collectively so as to compete towards different teams. This turns an anti-social exercise (competitors) right into a pro-social one (cooperation). Professional-sociality includes taking one other’s perspective, understanding their motivations, empathizing with their emotional state, and so forth. It additionally requires us to acknowledge that our wants should be balanced with the wants of others and to restrain our impulses to be pure “takers.”

These pro-social abilities helped some teams outcompete and overpower different teams. Maybe sarcastically, pure choice rewarded good cooperators and our species turned extra pro-social and emotionally related, a phenomenon typically described as “survival of the friendliest.” These abilities in cooperation, particularly empathy, self-restraint, and complicated communication all assist create social concord and peaceable decision of disagreements.

Cultural Group Choice

Constructing off of the notion that cooperative teams are extra profitable, teams of cooperative people with ever-growing brains started to build up sure cultural options that additional promoted each docility and aggressive success. These options type a type of “collective intelligence” of each abilities and information that grows from technology to technology. Whereas not encoded strictly in our genes, these cultural “memes” unfold in a lot the identical means that profitable genes do, a phenomenon that was most likely enhanced by genetic evolution in a course of referred to as gene-culture co-evolution.

Among the cultural options that promoted stability, concord, and a decline of violent intra-group battle embody 1.) Excessive capability for social studying; 2.) Growth and enforcement of social “guidelines;” 3.) Division of labor; 4.) Efficient punishment of social deviants; 5.) Existence of “popularity” (status) that impacts reproductive success; 6.) Self-marking of teams by means of symbols and different non-biological variations; and seven.) Institution of casual “establishments” by means of which collective motion brings group advantages. (You’ll be aware that a few of these overlap with different mechanisms lined right here. It is because cultural group choice is a idea in regards to the mechanism of choice, relatively than the exact options that have been chosen. It’s however an vital a part of the image.)


Self-domestication of people is an concept that dates again to Darwin himself, however is choosing up renewed momentum now that we’re starting to unravel the genetics of domestication. The concept is that people have undergone the identical sort of selective course of that our domesticated livestock and companion animals did. Whether or not its cows, canine, sheep, cats, goats, or chickens, domesticated animals are fairly totally different than their wild ancestors. They’re extra docile, extra tolerant, extra compliant, and fewer aggressive, and it is because, over hundreds of years, people bred probably the most docile ones and eradicated the most aggressive ones.

In comparison with our ancestors and our dwelling kin, people present this improve in docility as properly. Maybe an identical selective course of was at work as we domesticated ourselves: rewarding prosocial people and punishing violent ones. Sturdy help for this concept is present in a few of the different modifications that we see in domesticated animals in comparison with their wild ancestors: smaller enamel and mouth, smaller face, barely smaller brains, thinner jaw, smaller eye sockets, much less inflexible ears, and so forth. Fashionable people have all of those modifications as properly in comparison with our archaic ancestors (our brains are 10% smaller than our Neanderthal cousins, for instance).

We have now even found a genetic signature of the so-called “domestication syndrome” and, you guessed it, people have the signature.

Diminished Testosterone

Whereas we will’t measure testosterone ranges from fossils, there may be proof that common ranges of circulating testosterone has steadily dropped in our species over the past 300,000 years. This proof comes largely from modifications in our faces, as our forehead ridge has turn into much less distinguished and our faces have turn into extra rounded. These options are identified to correlate with variations in testosterone amongst dwelling people, so it’s inferred that our species skilled a gradual drop in testosterone amongst each sexes.

Throughout animal species, excessive ranges of testosterone correlate with aggression, violence, and male-dominated, conflict-based dominance regimes whereas decrease testosterone correlates with extra harmonious and egalitarian social buildings. Though considerably exaggerated within the fashionable creativeness, the distinction between aggressive and conflict-prone chimpanzees and their extra peaceable female-dominated cousins, the bonobos, helps this idea as the previous have markedly greater ranges of testosterone than the latter.

Tolerance of strangers

A ultimate human peculiarity that warrants point out is our tendency to be tolerant and accepting of strangers (so long as we understand them as members of our society). Mark Moffet has not too long ago superior this concept in a highly effective new ebook, The Human Swarm(which I overview right here). The concept is that, someplace alongside the road, human societies turned so giant that maintaining tabs on each single particular person turned too cognitively demanding. As an alternative, people did one thing that’s completely unthinkable for different apes: we developed belief that strangers aren’t a menace and we will peacefully co-exist with these with whom now we have no relationship in anyway (apart from being recognizable as members of the identical society).


Placing this all collectively, the social and cultural milieu of the final million years of human historical past has been marked by growing empathy, pro-sociality, altruism, and in-group cooperation. Whereas violence has all the time been part of our tradition, it has been in regular decline as our species transitioned to so-called behavioral modernity, a transition that continues to the current. Understanding the social, cultural, genetic, and hormonal roots of this decline provides nice promise for continued progress on the pacification and long-term success of our species.

[The above is highly condensed from my chapter The Decline of Violence in Spring/Nature’s new Encyclopedia of Evolutionary Psychological Science.]



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