Researchers Explain Reason behind an “Angry Face”

Rebecca Lewis September 01, 2014

That lowered brow, the thinned lips and the flared nostrils you see is what scientists call the "anger face”, and it appears to be part of the basic human biology.

Researchers at UC Santa Barbara and at Griffith University in Australia have identified the functional advantages that caused the specific appearance of the anger face to evolve.

"The expression is cross-culturally universal, and even congenitally blind children make this same face without ever having seen one," said lead author Aaron Sell, a lecturer at the School of Criminology at Griffith University in Australia. Sell was formerly a postdoctoral scholar at UCSB’s Centre for Evolutionary Psychology.

According to the new study, the ‘anger face’ seven distinct muscle groups that contract in a highly stereotyped manner. The researchers sought to understand why evolution chose those particular muscle contractions to signal the emotional state of anger.

The current research is part of a larger set of studies that examine the evolutionary function of anger. "Our earlier research showed that anger evolved to motivate effective bargaining behaviour during conflicts of interest," said Sell.

The greater the harm an individual can inflict, noted Leda Cosmides, the more bargaining power he or she wields. Cosmides, professor of psychology at UCSB, is a co-author on the study along with John Tooby, UCSB professor of anthropology. Cosmides and Tooby are co-directors of the campus’s Centre for Evolutionary Psychology.

"This general bargaining-through-menace principle applies to humans as well," said Tooby. "In earlier work we were able to confirm the predictions that stronger men anger more easily, fight more often, feel entitled to more unequal treatment, resolve conflicts more in their own favour and are even more in favour of military solutions than are physically weak men."

Considering this hypothesis, the researchers reasoned that the first step is communicating to the other party that the anger-triggering event is not acceptable, and the conflict will not end until an implicit agreement is reached.

"But the anger face not only signals the onset of a conflict," said Sell. "Any distinctive facial display could do that. We hypothesized that the anger face evolved its specific form because it delivers something more for the expresser: Each element is designed to help intimidate others by making the angry individual appear more capable of delivering harm if not appeased."

"Our previous research showed that humans are exceptionally good at assessing fighting ability just by looking at someone’s face," said Sell. "Since people who are judged to be stronger tend to get their way more often, other things being equal, the researchers concluded that the explanation for evolution of the form of the human anger face is surprisingly simple—it is a threat display."

"The function of the anger face is intimidation," added Cosmides, "just like a frog will puff itself up or a baboon will display its canines."

Source of this article:

The human anger face evolved to enhance cues of strength