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In my last post, I talked about some of the cultural factors Steven Pinker identifies that have led to a reduction in violence. There are two other major forces he discusses which are worthy of note.

The Flynn Effect

The first of these is a truly strange phenomenon. If you go by the results of IQ tests, average intelligence has been steadily rising for decades. This is called the Flynn effect, and it’s been found consistently in countries all around the world since IQ tests first started being administered around World War I. And what’s more, “the gains are not small: an average of three IQ points… per decade” [p.651]. To grasp the scale of this, Pinker writes that an average person from 1910 would test out as having an IQ of 70 today – the borderline of mental retardation.

Granted, intelligence is fluid and hard to measure, and IQ tests have often been criticized for cultural bias. But the sections of the tests that have shown the greatest improvement have to do with skills of abstract reasoning, like analogies or pattern matching, not culture-specific factual knowledge. Even steeper improvements have occurred over time in other tests of abstract intelligence, like Raven’s Progressive Matrices.

The causes of the Flynn effect are a subject of much debate. Better education? Better nutrition? A world where abstract reasoning skills are an increasingly important part of daily life and there’s more incentive to develop them? But whatever the causes, the effects are clear. Pinker argues that people of past eras were afflicted by what he dubs “moral stupidity” [p.659], thinking of other groups as subhuman and never making the obvious – at least, obvious to us – logical inferences that would have enabled them to see past their differences. These kinds of attitudes were shockingly common even in people thought of as statesmen or intellectuals – there are choice quotes from, say, Theodore Roosevelt (“the only good Indians are the dead Indians”), or Winston Churchill (who fondly recalled the “jolly little wars against barbarous peoples” he took part in).

Greater intelligence, on the other hand, leads to what Pinker calls the “escalator of reason” [p.650]. If I want to be treated decently, I have to argue that it’s wrong for you to hurt me. And once I accept this as a premise, a reasoning mind can take the trivial step of swapping the pronouns and realize that it’s just as logically valid to say that it’s wrong for me to hurt you. And once this insight is generalized to one group, it can be generalized to all groups. Like stepping onto an escalator, once you’ve taken the first step, all the rest follows from there.

What’s more, a more intelligent mind can perceive the greater benefits that come from cooperating in a Prisoner’s Dilemma scenario, and perceive when the other player also perceives this and will reason in the same way: what he calls “superrationality” [p.661]. In short, Pinker’s argument is that reason inevitably brings people to realize the benefits of cooperation versus the riskiness, wastefulness and stupidity of violence. To support this, he cites several different lines of evidence, including that people with higher IQs are more likely to choose cooperation in a Prisoner’s Dilemma game set up by psychologists, and that smarter people are less likely to commit violent crimes even when controlling for socioeconomic status.


Early on in the book, Steven Pinker makes a sweeping observation that may bruise the egos of those with a Y chromosome: “The one great universal in the study of violence is that most of it is committed by fifteen-to-thirty-year-old men” [p.104].

He speculates that there are evolutionary reasons for this: that violence is one of the ways that young men can secure an alpha-male reputation for themselves, and therefore higher social status and better odds of reproducing (as discussed in part 2); whereas women, since they invest much more in reproduction than men, have an evolutionary incentive to avoid risks that might harm their offspring.

But you don’t need to accept this hypothesis to accept the fact, which is backed up by experiment as well as by empirical observation. For example, in a computer experiment that simulated war games, giving players the options to negotiate with, threaten or attack each other over disputed resources, the overconfident players who engaged in unprovoked attacks or triggered mutually destructive retaliation were almost exclusively men [p.513].

If it’s true that men commit the majority of violence, then you’d expect that as women gain cultural and political power, violence would decrease. And that’s precisely what we see. “Historically, women have taken the leadership in pacifist and humanitarian movements out of proportion to their influence in other political institutions of the time” [p.685]. This doesn’t mean that all female leaders are peaceful – he cites Margaret Thatcher as one counterexample, and we can surely think of others – but merely that, on average, a society where women and men wield equal power will tend to be more peace-oriented than one where men predominate.

Feminism has had influence in the domestic sphere as well as the political arena, making violence within relationships less condoned. As recently as 1975, marital rape was not a crime in any state in the U.S. [p.400]; now it’s illegal in all of them. Rates of intimate-partner violence have also been declining for decades; surveys show that, although men are slightly more likely to condone domestic violence than women, the men of 1994 were less approving than the women of 1968 [p.409].

And it’s not just women who’ve benefited: “feminism has been very good for men” [p.412]. In the decades since the women’s movement, the rate of men being murdered by wives, ex-wives or girlfriends has fallen sixfold. Pinker’s explanation is that the arrival of women’s shelters, restraining orders, and other legal avenues leaves abused women with options to escape a violent, controlling partner other than killing him. (Until the 1970s, in many Western countries, family and friends could be charged with the crime of “harboring” if they gave shelter to battered women fleeing their abusers [!]).

On the other hand, there are some places in the world where feminism badly needs to make inroads. An imbalance of angry, frustrated, unmarriageable young men is a threat to societal stability, which is very bad news for India and China, two rising global powers where cultural forces favoring sons over daughters lead to epidemics of sex-selective abortion or simply abuse and neglect of girls. In China, traditional mores hold that parents are entitled to support in their old age from their sons, but not from their daughters (daughters are expected to support their in-laws), leading to the saying: “A daughter is like spilled water” [p.422]. In India, the problem manifests in the form of extortionate dowries.

Even if India and China stood alone in this respect, it would be enough to conclude that establishing full and equal rights for women, not just in law but in practice, is the major human-rights challenge of this century. Some of the causes of decreasing violence are mysterious, but this is one case where we know exactly what we need to do. Our world has already made more progress toward peace than past eras might have thought possible, but a world where women enjoy full legal and social equality might well make our time look, in distant retrospect, like a dark age.

Image credit: Shutterstock

Other posts in this series:

DAYLIGHT ATHEISM—Adam Lee is an atheist author and speaker from New York City. His previously published books include "Daylight Atheism," "Meta: On God, the Big Questions, and the Just City," and most...

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