The Elephant in the Brain: Hidden Motives in Everyday Life

by Kevin Simler

Body language, however, is mostly not arbitrary.14 Instead, nonverbal behaviors are meaningfully, functionally related to the messages they’re conveying. We show emotional excitement, for example, by being physically excited: making noise, waving our arms, dancing up and down.15 Or we show interest by widening our eyes and looking toward the thing we’re interested in, the better to take in visual information. Unlike words, which vary from language to language, most of these signals are shared across cultures.16 No society arbitrarily decides to convey interest by closing their eyes, for example, because the very meaning of interest implies a desire to pay attention and learn more.17 By the same principle, closing one’s eyes or looking away tends to convey some kind of aversion, like boredom or disgust. The point is, body “language” isn’t just a way to communicate. It’s also functional; it has material consequences. If we lunge aggressively toward another person, for instance, we better be prepared to fight. And owing to these consequences, body language is inherently more honest than verbal language. It’s easy to talk the talk, but harder to walk the walk. This is the principle of honest signaling, which we encountered in Chapter 2.18 Signals need to be expensive so they’re hard to fake. More precisely, they need to be differentially expensive—more difficult to fake than to produce by honest means.19