College yearbook photos are a gold mine for Positive Psychology researchers. “Look at the birdie and smile,” the photographer tells you, and dutifully you put on your best smile. Smiling on demand, it turns out, is easier said than done. Some of us break into a radiant smile of authentic good cheer, while the rest of us pose politely. There are two kinds of smiles. The first, called a Duchenne smile (after its discoverer, Guillaume Duchenne), is genuine. The corners of your mouth turn up and the skin around the corners of your eyes crinkles (like crow’s feet). The muscles that do this, the orbicularis oculi and the zygomaticus, are exceedingly difficult to control voluntarily. The other smile, called the Pan American smile (after the flight attendants in television ads for the now-defunct airline), is inauthentic, with none of the Duchenne features. Indeed, it is probably more related to the rictus that lower primates display when frightened than it is to happiness.
When trained psychologists look through collections of photos, they can at a glance separate out the Duchenne from the non Duchenne smilers. Dacher Keltner and LeeAnne Harker of the University of California at Berkeley, for example, studied 141 senior-class photos from the 1960 yearbook of Mills College. All but three of the women were smiling, and half of the smilers were Duchenne smilers. All the women were contacted at ages twenty-seven, forty-three, and fifty-two and asked about their marriages and their life satisfaction. When Harker and Keltner inherited the study in the 1990s, they wondered if they could predict from the senior-year smile alone what these women’s married lives would turn out to be like. Astonishingly, Duchenne women, on average, were more likely to be married, to stay married, and to experience more personal well-being over the next thirty years. Those indicators of happiness were predicted by a mere crinkling of the eyes. –Authentic Happiness by Martin Seligman