The Human Brain

The Human Brain

Thursday, July 26, 2007

The Adaptive Value of Exaggerated Strength: The Case of Violent Human Yells

“What is a human being in a rage? On my sacred honor, nothing but a human beast! The next time it happens to you, look at yourself in the glass; and you will find your soul gone out of you at your face, and nothing left but an animal—and a bad, a villainous bad animal, too!”
Wilkie Collins
Poor Miss Finch (1908)

Animals have evolved numerous strategies and adaptations to display their strength in order to avoid predation. Certain birds will puff up their feathers to appear larger than they truly are. Gorillas will bang on their chests. The hair of dogs and cats will stand on end. In some cases these adaptations warn potential predators of real dangers. For example, poisonous frogs are brightly colored to warn predators that if they eat them, it will be their last meal.

However, in some cases animals will bluff their predators. They will exaggerate their strengths and pretend to be more deadly than they are. Some animals will evolve bright colors akin to those of poisonous animals, but they will not be poisonous themselves. Chimpanzees will fly into a rage and shake trees in order to convince others in the group that he is powerful.

Humans are no exception. We are governed by the same rules as the rest of the animal kingdom. We fly into rages. At the annual meeting for the Human Behavior and Evolution Society in Williamsburg, Virginia, Aaron Sell presented some research findings that indicate the adaptive value of human violent yells.

Sell found that: 1 strength is detectable from voices, 2 the detection of strength from voices is cross-cultural, and 3 strength is exaggerated when the voice is a violent yell. More specifically, when participants listened to a violent yell, they had a tendency to overestimate height, weight, and strength of the yeller.

The next time that you fly into a rage, take Wilkie Collins’s advice and look at yourself in the mirror. Maybe you will recognize that you too are an animal. Maybe it will change your perception of what it is to be a human.