The Elephant in the Brain: Hidden Motives in Everyday Life

by Kevin Simler

Box 8: Signals versus Cues In biology, a signal is a behavior or trait used by one animal, the “sender,” to change the behavior of another animal, the “receiver.”9 Some signals are deceptive and used to manipulate the receiver, but most are honest, providing benefit to both senders and receivers.10 A peacock’s luxurious tail, for example, conveys information about the health and fitness of the male sender to one or more female receivers, and both parties benefit by using the signal to find mates. A cue is similar to a signal, in that it conveys information, except that it benefits only the receiver.11 In other words, a cue conveys information the sender might wish to conceal. Sometimes we refer to cues in the human realm as “tells”—like in the poker movie Rounders, when one character unconsciously twists open an Oreo whenever he has a winning hand. Other cues or tells can include sweaty palms (indicating nervousness), shortness of breath (indicating windedness from exertion), and pacifying behaviors such as rubbing one’s neck (indicating anxiety or discomfort).12 Cues are important for many students of body language, especially those—like poker players or police interrogators—who are hoping to read minds and sniff out deception. In this chapter, however, we’re concerned with (honest) signals, that is, traits or behaviors that help both senders and receivers coordinate their actions.