Human Anger Face Signal Of Strength
Christopher Philip
Researchers Aaron Sell, Leda Cosmides, and John Tooby argue in their paper that the anger face is not a random facial expression, but rather a specific display of physical strength in humans.
In fact, they argue that not only does the anger face showcase strength, but that the muscles used are far from arbitrary. In other words, they have a specific origin.
“Specifically,” say the researchers “during conflicts of interest, natural selection favored displaying those configurations of muscle activation that amplified others’ assessments of the sender’s fighting ability—in the human case, those configurations that amplified cues of strength.”
Thus, the anger face is a demonstration of a person’s fighting ability.
The study had subjects judge faces produced by a face generating software package. Faces were produced that demonstrated anger (lowered brow) or a control (raised brow) and the subjects were asked to rate the images based on their perceived strength.
The results showed that for each modification of the muscles used in producing that anger face, the more highly rated the images were for perceived strength.
The researchers also point out the male face is more prone to display anger more accurately due to more prominent cheekbones, wider noses, lower browridges, and larger chins. Additionally, the male of the species in other animals, has proven to be the most capable of inflicting fighting violence and exacting aggression. This alone suggest that the display of anger in humans by men is more effective in displaying strength.
In the specific study, however, they stimulus images were only depicted as male. It would have been interesting if female stimulus images had been compared.
As a bluff display, the anger expression would be important in dissuading challenges during potential conflict. This alone supports the facial expression and uniquely rewards its use and also its evolutionary persistence.
Certainly, in the past, physical conflict was more the norm than the exception, and those who could influence others to reduce their resistance to an aggressor’s desires, in non-physical ways, would reap the rewards.
As physical confrontation is particularly risky, evolution tends to favour those who can display ‘honest signals,’ that is, those who create signals that showcase actual strength versus feigned strength. Thus, the anger expression is believed by the researchers to help both the viewer of the expression, by reducing his chances of injury through a costly failed attack, as well benefit the displayer of the expression through fewer challenges overall.
Say the researchers, “Taken together, these data show that the constellation of facial muscle contractions comprising the anger expression is not arbitrary; instead, the anger face is well-designed to increase the perceived fighting ability of the angry individual during bargaining.”
Image Credit: Saurabh Vyas
Resources
Sell, A., Cosmides, L. and Tooby, J., The Human Anger Face Evolved to Enhance Cues of Strength. Evolution and Human Behavior. 2019, doi: 10.1016/j.evolhumbehav.2019.05.008