There is a dictatrix (female dictator) who is a well-intentioned extremist. She wants to make humans as peaceful as capybaras by only permitting humans who are empaths/sympaths to reproduce, humans who are sociopaths/psychopaths/narcissists/sadists are sterilized and even brutally killed (they are mauled and eaten by dogs trained to execute humans).

So, I wonder if it is possible to breed humans to be as peaceful as capybaras, as friendly as dogs, and as down-to-earth as earthworms? If so, what genes would be useful for having humans with these characteristics?

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    $\begingroup$ The problem is that any totally peaceful country will be overrun by the violent neighbors. These will breed their genes back into that population. See Genghis Khan and other nomadic leaders. $\endgroup$
    – David R
    Commented Oct 22, 2022 at 15:39
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    $\begingroup$ Also, selectively breeding humans is a very slow process, because our generations are so long. You can't make a meaningful start in one human lifetime. Your dictatrix needs to establish a fanatical institution that will stick to its mission for several hundred generations, several thousand years. That seems unlikely. $\endgroup$ Commented Oct 22, 2022 at 19:25
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    $\begingroup$ I'm not persuaded that empathy and docility are as closely related as some people think. Empathy for a victim can easily fuel resentment, even hatred, for the victimizer. $\endgroup$
    – Jedediah
    Commented Oct 23, 2022 at 14:38
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    $\begingroup$ @John Dallman blackmoth/white moth - 'evolution' can occur in a few generations or so if a) the genes are already in the population and b) selective breeding is enhanced. The dictatrix is doing both. $\endgroup$ Commented Oct 23, 2022 at 22:00
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    $\begingroup$ The opposite is true, too. Very bellicose cultures will quickly be overrun by their more reasonable neighbours. Nazism was one of the most violent doctrines in history, and Germany was destroyed 12 years after it came to power. $\endgroup$
    – wokopa
    Commented Jan 21, 2023 at 17:17

6 Answers 6


Sure. The primary feature of such a breeding program would be similar to the primary feature in dogs.

Docility is very much related to low intelligence.

Consider dogs. Domestic dogs of similar mass to a wolf have significantly smaller brains. This happened over roughly 1000 generations of selection by humans. Dog-ancestors that were aggressive or non-compliant did not get to stay around humans. They would be driven away or killed.

Consider cows. It is clear that aggressive breeds have relatively larger brains.

Humans breed domestic animals for docility by selecting the individuals that simply don't have ideas.

So, yes, it is possible to breed docility into humans. The result would be they would be relatively stupid.

  • $\begingroup$ I don't think that correlation generalises to humans. You can't make many confident predictions about people based on just animal models. $\endgroup$
    – wokopa
    Commented Jan 21, 2023 at 16:31
  • $\begingroup$ If animal results always trivially and definitely generalised to humans, it would be cheaper/quicker to just study mice. $\endgroup$
    – wokopa
    Commented Jan 21, 2023 at 17:18
  • $\begingroup$ This answer infers a lot while bringing too little evidence. $\endgroup$ Commented Jan 24, 2023 at 17:32

Can you do it? Sure!

In my answer to the question How to Domesticate the Hippo? I quote researchers about their efforts to domesticate the Russian Silver Fox:

The least domesticated foxes, those that flee from experimenters or bite when stroked or handled, are assigned to Class III. Foxes in Class II let themselves be petted and handled but show no emotionally friendly response to experimenters. Foxes in Class I are friendly toward experimenters, wagging their tails and whining. In the sixth generation bred for tameness we had to add an even higher-scoring category. Members of Class IE, the "domesticated elite", are eager to establish human contact, whimpering to attract attention and sniffing and licking experimenters like dogs. They start displaying this kind of behavior before they are one month old. By the tenth generation, 18 percent of fox pups were elite; by the 20th, the figure had reached 35 percent. Today elite foxes make up 70 to 80 percent of our experimentally selected population.

My conclusion to the question was simple:

I expect the same rules apply to Hippos ... assuming you can avoid the screaming and the yelling and the, well, death that might occur when you find Class III Hippos. Note that the experimenters had to work through 20 generations of foxes to just to achieve 35% domestication. with 6–8 years needed to reproduce a generation, that's 120–160 years to domesticate Hippos. Bring a sack lunch!

You have the same problems

Of course you can breed docile humans. Each generation you off those members of the group with undesirable aggressive tendencies and breed those that have the desirable peaceful tendencies. Of course, with 15-20 years needed to produce a generation (especially since many of your aggressive tendencies won't appear or mature until after puberty or even the beginning of adulthood), your dictatrix will need 300-400 years just to achieve 35% domestication. Hopefully she has a better-than-average geriatrics program.

But you also have consequences

It's very noble to believe humanity can weed out (or breed out) its aggressive tendencies. But that comes with a cost that far too many people don't believe. Breeding out aggression also means breeding out ambition, determination, the ability to face a challenge rather than flee from it (yup, fight-vs-flight gets stuck on flight.)

Most human innovation comes from facing a challenge. In fact, a LOT of human innovation came from war, conflict, and chaos.

So if your very-long-lived dictatrix achieves her goal of breeding peaceful humans, what she'll have are people perfectly content to do nothing. She'll have bred cattle that produces a good grade of long pork.

If what you're trying to do is believably have the best of all worlds (curious innovators who will never argue, much less fight), you'll discover that you can't have your cake and eat it, too. You can't have all the benefits of screaming defiance at the storm without having the occasional spouse beater (or megalomaniac... kinda the same thing, just a difference in scale), too.

BTW: If you want to see that domestication concept used as a plot device, go rent the movie "Serenity."


I'm working on a very similar world, btw. Dictatorship. Eugenics. Designed for harmony.

There are definitely genetic qualities associated with violence and aggression. By far the biggest one is BEING MALE. Males commit several times more violence than females in all human societies and throughout the animal kingdom. So your dictatrix could make maybe 80% of the population female (like in my world) and halve the violence rate at a stroke. (This would also lead to less violence born of male sexual frustration, at least a worldbuilder can get away with saying so.)

Some specific studies –

  • 5-10% of violence attributable to two particular genes, those with the genotype 13× more violence-prone

  • Heritability of violence estimated at 50% by: Tuvblad C, Baker LA. Human aggression across the lifespan: genetic propensities and environmental moderators. Adv Genet. 2011;75:171–214.

  • Zhang-James, Y., Fernàndez-Castillo, N., Hess, J. L., Malki, K., Glatt, S. J., Cormand, B., & Faraone, S. V. (2018). An integrated analysis of genes and functional pathways for aggression in human and rodent models. Molecular Psychiatry. doi:10.1038/s41380-018-0068-7 – this is an interesting study looking at 40 different genes identified in genome-wide association studies and how they interact on the same metabolic systems.

  • Veroude K, Zhang-James Y, Fernandez-Castillo N, Bakker MJ, Cormand B, Faraone SV. Genetics of aggressive behavior: an overview. Am J Med Genet B Neuropsychiatr Genet. 2016;1:3–43 – has a long list of genes on page 15, and also looks and twin studies, concluding "We know from twin studies that about half the variance in behavior may be explained by genetic risk factors. This is true for both dimensional, trait- like, measures of aggression and categorical definitions of psychopathology."

One thought: if the dictatrix has large-scale access to violent offenders, and their DNA samples, she could conduct this research better than Terran scientists can. There are a few GWAS (genome-wide association studies) on violence, but a centralised state with advanced biotechnology could run a comprehensive one on the entire population.

PS: I answered the question as asked, which is whether it's possible to make people more peaceful by genetics. As for "are peaceful human societies possible", the answer is obviously yes, as we have a lot of evidence of that. Let's look at the statistics from anthropology:

But that's not all attributable to genetic factors, which is what I tried to focus on at first.


Ghandi was born from parents which haven't made history for being extremely peaceful, and Hitler and Stalin were born from parents who didn't make it into history books for their cruelty.

I suspect the environment and experiences during development play a big role in determining the peacefulness/aggressiveness of somebody, more than just the genetic assett.

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    $\begingroup$ Picking specific examples is not a good way to find out the truth. You run into problems like sweeping generalisation and cherrypicking. $\endgroup$
    – wokopa
    Commented Jan 21, 2023 at 17:26

You can't - and I mean that technically.

Quis custodiet ipsos custodes?

Who watches the Watchmen?

In order to carry out violence against those the society deems undesirable (and forcibly kidnapping someone is violence - especially if it's to administer a death sentence) - then the Dictatrix needs people who are Violent.

Let's run through the scenarios - you can detect violent tendancies at Birth - you kidnap the baby - Ever heard of a Mamma Bear? There are numerous instances of Women (and Men too, but primarily women) doing near super-human feats to protect Babies.

Okay, so maybe not Babies, maybe we detect it in children? Same problem. Mothers will tear through whoever to protect their children. Dads too.

So let's then say - we wait till they are teenagers - an average Male Teenager is physically a match for an average Adult Female - in terms of Height, Weight, Speed, Strength - which means you will need average adult Men to enforce this.

I'm focussing on Men here - because we are bigger and more aggressive on average - and so are more likely to be the problem.

In order to weed-out those who would be Aggressive, the State will need to maintain a cadre of Humans that are Aggressive. This is your technical problem.

Ever facet of your scenario has an issue - in order to train dogs to kill Humans, sure it's not very difficult... But someone has to do it and that someone needs to have the aggressive instinct to control a Dog that knows how to kill a Human

Let's go with a tech solution - this is all done by killer-AI robots - a bit more plausible - even then though - someone has to program and maintain the Robots and be have a means of controlling them so they don't turn on their masters

Which leads to the other technical problem:

The threat of force and immediate overwhelming Violence is the best deterrent against Violence.

Consider two people standing on a street corner. One is all hunched over looking around nervously, weighing 60 KG dripping wet and looks like they've never had a touch of testosterone in their life.

The other is a 6 ft something musclebound behemoth, with an LMG slung over their shoulder and a T-Shirt that says 'Fuck around and Find out'.

Which one are you more likely to try and victimize?

And the follow-up - if both of them are being mean to you - which one are you going to take a swing at and hope for the best?

  • $\begingroup$ "someone needs to have the aggressive instinct to control a Dog that knows how to kill a Human" – this is not how dogs are trained. It's mostly a matter of treats and clicks. Read Don't Shoot the Dog by Karen Pryor $\endgroup$
    – wokopa
    Commented Jan 22, 2023 at 23:59
  • $\begingroup$ @wokopa - Clicker training and treats are good, yes. But confidence which is predicated on the notion that I'm not scared of you because I am capable of destroying you is another factor - Nervous people who are scared of dogs are more likely to be bitten by dogs. If you have had all aggression bred out of you and you are faced with a dog that you know can kill you and you lack the means to fight back - how nervous do you think you are going to be? $\endgroup$ Commented Jan 23, 2023 at 0:05

I don't think it is possible to alter personality by changing genes, it is entirely too complex. You say "as friendly as dogs" but there are still mean dogs that exist. The only way to really alter personality is through social means. By choosing who can remain in the group and who should be cast out. But then you run into the problem of deciding who decides and how to monitor the decider. We have evidence of that around the world, groups of passive, compliant people and groups of genociders. The fortunate thing about humans is that 90% get along well with others and cooperate with other groups, but you will always have a small percentage of extreme outliers either totally passive doormats (what your dictatrix wants to create) or evil active monsters (the dictatrix). None of that is determined by genes, nature vs nurture.

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    $\begingroup$ You don't think personality can be changed by altering genes. You would be incorrect. Google search for "genetics of personality disorders" then click on Scholarly Articles and you will get 446,000 results. Lots of personality aspects are strongly influenced by genetics. $\endgroup$
    – BillOnne
    Commented Oct 22, 2022 at 15:51

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