THREAD: Sex Differences in Aggression

According to a recent New York Times piece, boys are more violent than girls – but their tendency to violence isn't innate. https://www.nytimes.com/2019/03/30/opinion/sunday/boys-men-violence.html

Certainly, socialization matters. But biology matters as well. Here's how we know... 1/10

First, "we spend a lot more time discouraging male aggression than female… Males, it seems, are more aggressive *despite* culture, not because of it." https://www.amazon.com/Ape-that-Understood-Universe-Culture/dp/1108732755/ #TheApeThatUnderstoodTheUniverse 2/10

"By clamping down on male aggression, culture may sometimes make the sex difference in aggression *smaller* than it would otherwise have been." https://www.amazon.com/Ape-that-Understood-Universe-Culture/dp/1108732755/ #TheApeThatUnderstoodTheUniverse 3/10

Second, "the sex difference in aggression appears very early in life… [and] remains static until puberty… If socialization creates the sex difference, why doesn't continued socialization before puberty pry the sexes apart?" https://www.amazon.com/Ape-that-Understood-Universe-Culture/dp/1108732755/ 4/10

Third, "as with many sex differences, the sex difference in aggression suddenly swells at puberty… Is it just a coincidence that this comes at the same time as the massive surge in circulating testosterone that accompanies puberty in males?" https://www.amazon.com/Ape-that-Understood-Universe-Culture/dp/1108732755/ 5/10

Fourth, "male aggression steadily nosedives through the remainder of the lifespan. The socialization hypothesis offers no particular reason to expect this." https://www.amazon.com/Ape-that-Understood-Universe-Culture/dp/1108732755/ #TheApeThatUnderstoodTheUniverse 6/10

Fifth, sex differences in aggression are a cross-cultural universal. In every culture on record, for instance, men commit the vast majority of homicides (and are more likely to be the victims of homicide as well). http://www.unodc.org/documents/gsh/pdfs/2014_GLOBAL_HOMICIDE_BOOK_web.pdf http://nautil.us/blog/nurture-alone-cant-explain-male-aggression 7/10

Sixth, contrary to the idea that sex differences are a product of gender roles, sex differences in adolescent physical aggression are larger, not smaller, in more gender-equal nations (N = 247,909) https://onlinelibrary.wiley.com/doi/epdf/10.1002/ab.21799 http://nautil.us/blog/nurture-alone-cant-explain-male-aggression 8/10

Finally, comparable differences are found in many other species. For example…

Humans: Males commit 95% of homicides and are 79% of homicide victims http://www.unodc.org/documents/gsh/pdfs/2014_GLOBAL_HOMICIDE_BOOK_web.pdf

Chimps: Males commit 92% of chimpicides and are 73% of chimpicide victims https://www.nature.com/articles/nature13727 9/10

For more on the origins of human sex differences, check out Chapter 3 of my book The Ape That Understood the Universe – featuring a new foreword by the inimitable @MichaelShermer! https://www.amazon.com/Ape-that-Understood-Universe-Culture/dp/1108732755/ 10/10