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Justice Is in Our Nature

The views expressed are those of the author and are not necessarily those of Scientific American.

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Social contracts are written into our biology. As is the justice they need. The arc of our evolution has long bent towards the justice of “laws” fittest for team survival. We bred ourselves, by artificial selection, to internalize and feel strongly about social rules.

Christopher Boehm in Moral Origins concludes, after intensive analysis of 50 representative hunter-gatherer cultures, that our ancestors likely experienced a “radical political change,” evolving from a hierarchic “apelike ‘might is right’…social order,” to become more egalitarian. About 250,000 years ago, their survival became a team sport because chasing big-game toward teammates was much more productive than solo hunting. But only if profit-sharing was sustainable. Even with fit teammates hunting needs luck (e.g. 4% success today). Then, as now, the logic of social insurance solved team problems by sharing profits and risks. Productivity gains in interdependent teams radically changed our evolution. Cooperators thrived. As did teams with the best adapted sharing rules, provided they were well enforced.

Boehm says all surviving hunter-gatherers enforce law-like social rules to prevent excessive egoism, nepotism, and cronyism. They use rebukes, ridicule, shame, shunning, exile and execution (typically delegated to close male kin of the condemned, to avoid inter-family feuding). For example, meat isn’t distributed by the successful hunter but by neutral stakeholders. Excessively dominant alpha-male behavior—like hogging more than a fair share of meat—is punished by “counterdominant coalitions.” If the strong abused their power they were eliminated, in a sort of inverted eugenics. Resisting injustice and tyranny are universal traits in today’s hunter-gatherers. They likely run 10,000 generations deep in our prehistory.

Social punishment created powerful selection pressures. Self-control becomes the lowest-cost strategy for avoiding social penalties. Shame and guilt likely evolved as mechanisms for internalizing the logic of team rules—a social contract written into our biology. We intuitively recognize what is considered punishable. And often punish ourselves. Cultures configure shame and guilt system triggers differently. But rules balancing short term individual selfish gain with longer-term or team interests are more evolutionarily productive. Thinking of our evolved urges as irresistible is a deep error, since self-control, especially relative to social rules, has long been needed for survival (see “evo-irresistible error”)

Our ancestors bred themselves to be team players. They used intelligently directed artificial selection of good cooperators as mates (“auto-domestication”). Bad cooperators were less likely to be selected for, or successful at, the hugely costly and highly collaborative business of raising long helpless offspring.

Justice, wrote Hesiod, poet of the ancient Greek masses and Homer’s rival, was “Zeus’s greatest gift” to us. Greatest or not, without it human nature wouldn’t be what it is. And we wouldn’t exist.

Illustration by Julia Suits, The New Yorker Cartoonist & author of The Extraordinary Catalog of Peculiar Inventions.

Previously in this series:

It Is in Our Nature to Be Self-Deficient
Inheriting Second Natures
Our Ruly Nature
It Is in Our Nature to Need Stories
Tools Are in Our Nature
We Fit Nature To Us: Evolutions two way street

Jag Bhalla About the Author: Jag Bhalla is an entrepreneur and writer. His current project is Errors We Live By, a series of short exoteric essays exposing errors in the big ideas running our lives, details at His last book was I'm Not Hanging Noodles On Your Ears, a surreptitious science gift book from National Geographic Books, details at It explains his twitter handle @hangingnoodles Follow on Twitter @hangingnoodles.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. jgrosay 1:28 pm 05/30/2013

    ‘Justice’ means the condition of being right, being good, being saint; what most of us associate when we hear or read the word ‘Justice’ would be better called ‘the law’, ‘the court’, or something like, even the Bible speaks about ‘promoting justice and law’, so it’s not the same.

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  2. 2. Bill_Crofut 1:32 pm 05/30/2013

    Re: “Social contracts are written into our biology.”

    That statement reads nearly identically to one much older:


    2:14. For when the Gentiles, who have not the law, do by
    nature those things that are of the law; these, having not
    the law, are a law to themselves.

    2:15. Who shew the work of the law written in their hearts…

    [Catholic Bible. (c) 2000. Douay Rheims translation. Murray, KY: A production of Catholic Software.]

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  3. 3. Quentin 2:00 pm 05/30/2013

    I think there is a difference here. St Paul is speaking about a sense of moral obligation, whereas the article is talking about an evolved instinct. One is entitled to ignore an evolved instinct if one so wishes, but not entitled to ignore a recognized moral obligation. Instinct and morality may support each other but they are of a different order.

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  4. 4. Bill_Crofut 9:19 am 05/31/2013


    It’s my bet you’re correct about intent in this text as opposed to Scripture, but it brings up an interesting question. What is the evidence for the “evolution” of the instinct?

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  5. 5. hangingnoodles 12:22 pm 05/31/2013

    All (& replying to @Quentin @jgrosay and @Bill_Crofut):

    The evidence of a culturally configurable instinctive morality is what Chris Boehm’s book details (in 400 pages). I tried to extract key point in my post above. More posts to follow on this.

    But you may be interested in this long quote of what Jefferson had to say on the subject: See point 3 here (quoted below)

    “He who made us would have been a pitiful bungler, if he had made the rules of our moral conduct a matter of science. For one man of science, there are thousands who are not. What would have become of them? Man was destined for society. His morality, therefore, was to be formed to this object. He was endowed with a sense of right and wrong merely relative to this. This sense is as much a part of his nature, as the sense of hearing, seeing, feeling; it is the true foundation of morality… The moral sense, or conscience, is as much a part of man as his leg or arm. It is given to all human beings in a stronger or weaker degree, as force of members is given them in a greater or less degree. It may be strengthened by exercise, as may any particular limb of the body. This sense is submitted indeed in some degree to the guidance of reason; but it is a small stock which is required for this: even a less one than what we call Common sense. State a moral case to a ploughman and a professor. The former will decide it as well, and often better than the latter, because he has not been led astray by artificial rules.” –Thomas Jefferson to Peter Carr, 1787. ME 6:257, Papers 12:15

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  6. 6. Bill_Crofut 11:20 am 06/1/2013


    The Jeffersonian quote is interesting, but far more interesting to me is your statement: “More posts to follow on this.”

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