Darwin and the Evolution of Expression

An experiment on 4-month-old Willy Darwin led to a lifelong study of expressions — and to breakthroughs in psychology.

 ONE DAY in May of 1840, a young scientist in London did something that will sound strange to any new parent: He deliberately startled his 4-month-old son, provoking piercing squalls from the baby and probably a baleful glare from his wife. Then he did it again.

WHAT I LEFT OUT is a recurring feature in which book authors are invited to share anecdotes and narratives that, for whatever reason, did not make it into their final manuscripts. In this installment, James T. Costa shares a story that was left out of his new book, “Darwin’s Backyard: How Small Experiments Led to a Big Theory” (W.W. Norton).

The scientist was Charles Darwin, and the experiment on his son Willy turned out to be an often-overlooked landmark in the history of science. Darwin, then just 31 years old, had become a convert to the field of “transmutation,” as evolution was called then, and had experienced an epiphany when he discovered its driver, which he dubbed natural selection. The former theology student immediately grasped the implications of this theory, declaring that the theological interpretation of the natural world had been undone by scientific evidence — “The fabric falls!” as he put it in a notebook. And while Darwin remains best known for his world-shaking theories on plant and animal evolution, as put forward in the 1859 book “On the Origin of Species,” people and society were never far from his mind.

Convinced of the evolutionary unity of life, Darwin naturally saw humans as part of the tapestry: They were animals too, after all. (Carl Linnaeus may have been deliberately provocative when, in 1758, he derived the taxonomic name “primates” from the Latin for “prime” or “first rank,” to refer not only to humans but to monkeys and apes; it also happened to be the term applied to bishops.) The standard view of the time was that, despite superficial similarities, there was no true relationship between humans and other primates, let alone other animals. Weren’t we humans clearly endowed with a soul and mental qualities that set us apart from and above the animal kingdom? But Darwin saw deeper significance in the family relationship, one of continuity, and common descent. To him, there was no real gap between people and primates — differences, yes, but of degree and not kind. “Origin of man now proved,” he declared in 1838. “He who understands baboon would do more towards metaphysics than Locke.”

But it wasn’t enough to base that argument on anatomy alone. So in the same spirit that he applied to other pinnacles of evolutionary perfection — notably vertebrate eyes and bees’ cells — Darwin resolved to search for evidence of the animal origins of our very emotions and mental endowments. He saw that just as the study of anatomical stages can give insight into the origin and evolution of specialized structure, so too can the study of mental development reveal pathways for highly developed cognitive abilities. Both, too, can inform species relationships. In an 1838 notebook, “Metaphysics on morals and speculations on expression,” Darwin posed questions to himself, scrawled on the inside back cover under the heading “Natural History of Babies”: `

Source https://undark.org/2017/11/03/wilo-darwin-evolution/ accessed 9th July 2022

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