How the human 'angry face' evolved

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It may not be as menacing as a lion's roar or a snake baring its fangs, but scientists now believe that the human 'angry face' evolved to make us look 'really tough'.

The scowl people pull when they are infuriated may be more than a way of communicating their frustrations, researchers at the University of California, Santa Barbara have found.

Flared nostrils, a lowered eyebrow and a jutting jaw are all characteristics that make a person seem physically stronger, and may have been used to make opponents back down in times gone by.

According to The Times in the UK, Aaron Sell, who led the research, said: 'The reason natural selection designed [the angry face] is that the individuals who made the face out-reproduced the other ones.

'They out-reproduced them because the people who made that face won their conflicts. The other people back down because they thought, "Wow, he looks really tough."'

Dr Sell added: 'In many animal species, before aggression, animals will pose in ways that enhance the cue of fighting ability that they have.

'Hair can stand on edge to make the mammal seem larger; lips are pulled back to make fangs look as large as possible.'

The new study, published in the Evolution and Human Behavior journal, involved scientists testing different features of the angry face on people's expressions.

The experts said the seven characteristics of the human scowl are flared nostrils, thinned lips, the chin pushed up and out, the cheekbone and mouth raised, and the brow lowered.

They gradually added the features to a computer-simulated face, asking volunteers to say which person looked the strongest.

The volunteers said the faces with more 'angry features' belonged to stronger men.
Dr Sell said: 'Since people are judged to be stronger tend to get their way more often, other things being equal, we concluded that the explanation for evolution of the form of the human anger face is surprisingly simple - it is a threat display.'

Another study of the anger face, in 2005, suggested that the look made people appear more threatening as they seemed older.

However, Dr Sell's research contradicts their findings, as another experiment by his team found that people did not rate the computer-generated angry faces as any older than neutral, control images.

- Mail On Sunday