During a study to understand why people make similar faces to display anger, researchers learned that angry faces make people appear stronger.
The face of a human being has seven distinct muscle groups that contract in the same way for all people regardless of location, class, gender, or any other potential differences.
"The expression is cross-culturally universal, and even congenitally blind children make this same face without ever having seen one," says Aaron Sell, lead author of the study and lecturer at the School of Criminology at Griffith University in Australia.
This observation suggests that an angry face is a natural response for human beings and that it is supposed to communicate a specific message. Sell believes they have found the answer.
"Our earlier research showed that anger evolved to motivate effective bargaining behavior during conflicts of interest," Sell says.
The initial hypothesis is that anger is a "bargaining emotion," the first step is to show that an anger-triggering event is not okay, and the dispute will not end until an agreement is met that satisfies both sides.
According to the research, anger is meant to intimidate the other side. It delivers a warning of the dire consequences that will come about if the angry party is not pleased.
Furthering their hypothesis, researchers assumed that our ancestors believed that greater upper body strength meant more potential for harm which would make an angry person appear stronger.
Researchers took notes of computer generated angry faces to note which parts of the face create the intended effect. The most common feature of angry faces is a lowered brow. For comparison, one photo was shown with a lowered brow adjacent to a picture of a raised brow.
"With just this one difference, neither face appeared 'angry,'" says Sell. "But when these two faces were shown to subjects, they reported the lowered brow face as looking like it belonged to a physically stronger man."
As one might expect, the angry face is considered an instinctual way of giving a threat like when a frog puffs its chest or a baboon shows its canines.
The study confirms what we always assumed but never knew with certainty. Further clarity in the study can only serve to benefit us all.
