When Europe became Christian, the death penalty was abolished. Right up until the beginning of the Middle Ages, people were left to settle their own disputes by fighting each other or demanding, from the state, that the murderer pay a fine for killing their relative. But, as Frost and Harpending put it, the Church gradually came to accept that, the "wicked" should be executed "so that the good can live in peace."Democracy is just not good at doing things like culling the psychopaths. On the contrary, we get things like same-sex marriage, that nobody argues is good for society, but which is court-ordered based on individual rights to see death certificates.
With biblical justification, more and more crimes became subject to the death penalty. By the High Middle Ages, every single felony (any crime serious enough to have traditionally warranted the confiscation of property) was met with the hangman’s noose.
Those sent to the gallows were almost always high-testosterone young men prone to violent crime. In fact, Frost and Harpending calculated that one percent of the male population were executed every generation throughout the Middle Ages. And another one percent were killed at the scene of the crime or died in fetid prisons awaiting trial or execution. So two percent of young men were eliminated every generation.
And because they tended to be young, this process meant that they had fewer children than if they hadn't been executed. Thus, they would have passed on fewer of their genes.
It’s here that Frost and Harpending perceptively draw their conclusion. Capital punishment must have changed the nature of European personality—by, in effect, culling out the psychopaths. ...
Frost and Harpending are clear: Widespread execution led to the genetic "pacification" of Western Europe. It made people more cooperative, more forward-thinking, less impulsive . . . in other words more psychologically able to develop civilization. And as the late Canadian psychologist J. Philippe Rushton showed in his 1995 book Race, Evolution and Behavior, that it is the ethnic groups with these personality traits that develop civilization.
More recently, anthropologist Edward Dutton and Swedish psychologist Guy Madison have taken this insight further. In a 2018 article in the journal Evolutionary Psychological Science [Execution, Violent Punishment and Selection for Religiousness in Medieval England] they point out that this system of widespread execution would also have selected strongly for intelligence. Low socioeconomic status is predicted by low intelligence and it was overwhelmingly young, low SES men who met the hangman's noose. Low IQ predicts living for the now and not thinking about the future. And considering the dire consequences of breaking the law up until the 19th century, in England for example, you’d have to have been fairly stupid to do it.
And it is quite clear that national-average intelligence is the motor of civilization.
China is probably working on a system today to score the worth of each citizen. Someday the low-scoring citizens will be sterilized or executed.
I suspect that Europe's history of warfare has also bolstered its genetic stock. People celebrate peace, as if that is a good thing, but war also may be essential to civilization. Psychopaths may be essential also. We will want to keep some of them.