‘The WEIRDest People in the World’: How cultural evolution changes the brain

Nature or nurture? It’s an age-old debate that has produced pronouncements like, “This little girl takes after her father,” and “The boy looks just like his grandmother.” But Francis Galton, Charles Darwin’s clever cousin, brought the debate into the academic arena in the late 19th century. Darwin was a serious and conscientious scientist. Galton was an intense polymath, eager to use the principles of evolution to explain human societies. He invented eugenics and social Darwinism, two theories that would reserve him a place in the history of human infamy. But stripped of all their political and economic interpretations, his scientific ideas are still being actively debated today. So much for the nature theory.

The nurture theory reached its peak popularity a few decades later with the arrival of B.F. Skinner, the influential behaviorist who convinced 20th-century academia that humans are born with “blank slate” brains, and any environmental stimuli could write on that slate. Skinner believed so strongly in social engineering that he once invented an “air crib” for infants, a sealed, microbe-free, air-conditioned and soundproof enclosure. Skinner believed this was the optimal environment for raising babies until they were two years old. Starting in the 1950s, Skinner used his Harvard pulpit to influence generations of psychologists, an influence that persists to this day. Genetics is still a bad word in university humanities courses. So much for parenting.

Without human genes, we would not be able to learn to read and write. But the acts of reading and writing themselves modify the brain

Joseph Henrich’s extraordinary book, The WEIRDest People in the World (Farrar, Straus and Giroux, 2020), resolves the nature-nurture debate with dazzling eloquence. Settling such polarized arguments often requires climbing a ladder to a second-floor balcony and watching the contradictions vanish. The two opposing ideas are revealed as parts of a more abstract, profound and fruitful reality. It is not nature or nurture, but nature then nurture, and nurture then nature.

Without human genes, we would not be able to learn to read and write. But the acts of reading and writing themselves modify the brain. That is the essence of Henrich’s argument in his lengthy book. It’s the Western people of the world who are the weird ones alluded to in the book’s title. Henrich attributes this weirdness to the very high literacy rates of developed countries, still a rarity among the 1,000 or so diverse cultures on our planet. This is not because Westerners are born smarter, but because our societies and political systems have made us literate. And this has changed our brains. Nurture then nature.

The author has convincing qualifications. A professor and chair of the Department of Human Evolutionary Biology at Harvard University, anthropologist and space engineer, he has led teams researching the behavior of different human societies. This research has led him to conclude that the subjects of most psychology research – Western citizens – are very peculiar. Henrich winkingly calls them WEIRD, an acronym that stands for Western, Educated, Industrialized, Rich and Democratic. It’s an important insight because it implies that the discipline of contemporary psychology is guided by a very skewed sample of the human species. Western citizens cannot be extrapolated to other cultures.

The WEIRDest People in the World is not a book for neuroscientists or anthropologists. Its target audience is educated readers of all types. There is no doctrine or dogma, simply arguments based on sound research, including the author’s own. Henrich takes the reader by the hand through a complex reality – our species is complex – showing how a scientific approach led to his conclusions, however shocking they may be. It’s a refreshing approach in a nonfiction landscape littered with baseless opinions. Henrich follows in the footsteps of Jared Diamond, the American academic for whom anthropological sensitivity and scientific creativity peacefully coexist on the second-floor balcony. Both authors are contemporary intellectuals who have transcended the myopic academic boundaries that constrain so many.

Learning to read and write modifies the brain in a very interesting way. Just above and behind the left ear is the occipitotemporal cortex of the brain, where processors that interpret spoken language and recognize objects dwell. Spoken language is intimately associated with human nature, and has played a leading role in the evolution of our species for hundreds of thousands of years. Writing, on the other hand, was only invented about 6,000 years ago, not enough time for genetics to adapt and develop a built-in writing organ. Instead, a literate culture creates a new processor among the language and object recognition processors, one that is responsible for perceiving very special objects – letters and words.

There are even more differences between Western populations and other cultures, including spatial reasoning, attention, memory, perceptions of fairness, risk-taking, pattern recognition, inductive reasoning and even susceptibility to optical illusions. Culture changes the brain, and that’s why Westerners like us are the weirdest people in the world. Read the book.