Sometimes it’s even necessary to do something risky or wasteful in order to prove that you have a desirable trait. This is known as the handicap principle. It explains why species with good defense mechanisms, like skunks and poison dart frogs, evolve high-contrast colors: unless it can defend itself, an animal that stands out quickly becomes another animal’s lunch. For a nonbiological example, consider the difference between blue jeans and dress pants. Jeans are durable and don’t need to be washed every day, whereas dress pants demand a bit more in terms of upkeep—which is precisely why they’re considered more formal attire.
In the human social realm, honest signaling and the handicap principle are best reflected in the dictum, “Actions speak louder than words.” The problem with words is that they cost almost nothing; talk is usually too cheap. Which is a more honest signal of your value to a company: being told “great job!” or getting a raise?
We rely heavily on honest signals in the competitive arenas we’ve been discussing—that is, whenever we try to evaluate others as potential mates, friends, and allies.