Alan Burdick in Nautilus:
In a study published in 2011, Sylvie Droit-Volet, a neuropsychologist at Université Blaise Pascal, in Clermont-Ferrand, France, and three co-authors showed images of the two ballerinas to a group of volunteers. The experiment was what’s known as a bisection task. First, on a computer screen, each subject was shown a neutral image lasting either 0.4 seconds or 1.6 seconds; through repeated showings, the subjects were trained to recognize those two intervals of time, to get a feel for what each is like. Then one or the other ballerina image appeared onscreen for some duration in between those two intervals; after each viewing, the subject pressed a key to indicate whether the duration of the ballerina felt more like the short interval or the long one. The results were consistent: the ballerina en arabesque, the more dynamic of the two figures, seemed to last longer on screen than it actually did.
That makes a certain sense. Related studies have revealed a link between time perception and motion. A circle or triangle that moves quickly across your computer monitor will seem to last longer on screen than a stationary object does; the faster the shapes move, the bigger the distortion. But the Degas sculptures aren’t moving—they merely suggest movement. Typically, duration distortions arise because of the way you perceive certain physical properties of the stimulus. If you observe a light that blinks every tenth of a second and simultaneously hear a series of beeps at a slightly slower rate—every fifth of a second,1 say—the light will seem to you to blink more slowly than it does, in time with the beep. That’s a function of the way our neurons are wired; many temporal illusions are actually audiovisual illusions. But with Degas there’s no time-altering property—no motion—to be perceived. That property is entirely manufactured by, and in, the viewer—reactivated in your memory, perhaps even reenacted. That simply viewing a Degas can bend time in this way suggests a great deal about how and why our internal clocks work as they do.
One of the richest veins in temporal-perception research is on the effect of emotion on cognition, and Droit-Volet has conducted a number of compelling studies that explore the relationship. In a recent series of experiments, her subjects viewed a series of images of faces, each of which was neutral or expressed a basic emotion, such as happiness or anger. Each image lasted onscreen for anywhere from 0.4 seconds to 1.6 seconds, and the viewer was asked to say whether the image lasted for a “short” or a “long” time—that is, closer to one of the two standard durations they’d been trained beforehand to recognize. Consistently, viewers reported that happy faces seemed to last longer than neutral ones, and both angry and fearful faces seemed to last longer still. (The angry faces lasted even longer to 3-year-old children, Droit-Volet found.)