Born to Be Good: The Science of a Meaningful Life

Why do our emotional expressions look as they do? Why does anger, for example, have the furrowed brow, upper eyelid raise, and tightened, clenched mouth? Why does it not involve any of the thousands of other possible facial muscle combinations? To answer this question, Darwin invoked three principles of expressive behavior. According to the principle of serviceable habits, expressive behaviors are vestiges of more complete actions that have led to rewarding outcomes in our evolutionary history. As a result, they tend to re-occur over time and become reliable signals of internal states and likely actions. Disgust, for example, looks as it does with wrinkled nose, flared nostrils, open mouth and protruding tongue because it is the vestige of vomiting, and signals our experience of revulsion when noxious substances enter the mouth or are at risk of doing so (or noxious ideas risk contaminating the mind). The facial expressions we observe today are a rich shorthand for communicating the possibility of more full-bodied actions—attack, flight, embrace.

Darwin arrived at his second principle of expressive behavior—the principle of antithesis—in part from observations of his stable dog Bob. One of Bob’s characteristic displays was the “hot house face,” a sullen canine display of drooping head, ears, and tail. Darwin reliably observed this display when Bob was denied pleasure—a run with Darwin in the country, for example. Bob’s display, which charmed Darwin so, took the opposite form of the upright ears, head, and tail seen when Bob merrily ran alongside his owner. Here Darwin discerned a broader principle organizing this endearing display of disappointment: the principle of antithesis, which holds that opposing states will be associated with opposing expressions. One of the clearest signs of dominance, shown by alpha apes, CEOs, and pedantic professors alike, is the arms and head akimbo. In this display the individual expands the chest, holds clasped arms behind the head, and leans back. This signal of dominance is the diametrical opposite of the signs of weakness and impotence (see table)—head movements down, shoulder constriction.

Finally, in good Victorian fashion, Darwin held that certain expressive behaviors were organized according to the principle of nervous discharge. This principle holds that excess, undirected energy is released in random expressions, such as head scratches, face touches, leg jiggles, nose tugs, hair twists, and the like. One prevailing metaphor of emotion, at the very heart of Freud’s theory of emotional conflict and the psychodynamic mind, is that emotions are like fluids in containers. We boil over, blow our top, get steamed, and feel ready to explode during numerous states, from anger to rapturous ecstasy to sexual desire. Many emotional states, therefore, should produce seemingly random behaviors that reflect the intrapsychic hydraulics of emotion. We tug at our hair when nervous, shake our head when embarrassed, and bite our lips when feeling desire and the impulse to hop in the sack with our dinner date.

This extraordinary culling, sifting, and winnowing of observations of humans and nonhumans left Darwin exhausted and in physical pain at the end of each day of writing, but he turned quickly to his Expression book. As he parsed the realm of expressive behavior, tracing it back to our primate predecessors, he realized the critical data that he lacked: a study that would address whether facial expressions are universal to a human species shaped by a common history of selection pressures. He queried English missionaries in other countries (receiving thirty-six responses) about whether they had observed expressions not seen in Victorian England. They had not. Of course, Darwin’s manner of asking the question may have encouraged the answers he sought. He returned to his notes about his encounters with the indigenous peoples of Tierra del Fuego, Tahiti, and New Zealand during his five-year voyage on the Beagle. When Darwin met the Fuegians, who greeted the passengers of the disembarking Beagle naked, with arms flailing and long hair streaming, Darwin was the first to make friends with them by reciprocating their friendly chest slaps. Perhaps in those recollections he saw signs of universal human expression. The definitive data, however, would come 100 years later, in the paradigm-shifting research of Paul Ekman.

IN THE HIGHLANDS OF NEW GUINEA