SAY CHEESE: For his emotion experiment, Darwin selected photographs from a collection by French physiologist Guillaume-Benjamin-Armand Duchenne, who was studying the facial muscles responsible for expressions. Duchenne re-created facial expressions of volunteer subjects by harmlessly stimulating muscles of the face with an electrical probe. Duchenne termed the expression depicted above “grimace,” while Darwin called it “laughter.”DAR.LIB.160 REPRODUCED BY KIND PERMISSION OF THE SYNDICS OF CAMBRIDGE UNIVERSITY LIBRARYDo upturned lips and sparkling eyes always suggest happiness? Is shock and awe regularly conveyed by a furrowed brow and gaping mouth? Do we learn to interpret such cues, or do we inherit an understanding? Charles Darwin began to speculate about the interplay of emotions, expression, and inheritance in the 1830s while traveling aboard the HMS Beagle. And in 1868, he designed a novel experiment he hoped would answer these questions—an experiment so intriguing that modern-day researchers at the University of Cambridge decided to repeat it.
Darwin’s study took advantage of the new technology of photography to assess people’s reactions to various facial expressions. He showed participants photographs of people whose faces were artificially contracted by harmless electrical probes into expressions resembling those of emotions ranging from happiness to deep grief. He then asked viewers to interpret the expressions. These studies confirmed for Darwin his long-held opinion that expressions are universally understood, across languages, cultures, and even species—an opinion that had sprouted during the Beagle voyage from his observations of “human-like” expressions of animals. In his 1872 book The Expression of the Emotions in Man and Animals, Darwin wrote that “the young and the old of widely different races, both with man and animals, express the same state of mind by ...
