Valparaiso, Chile High school students protest about changes to the public state education system in Valparaiso, 137 km (85 miles) northwest of Santiago June 5, 2006
Valparaiso, Chile High school students protest about changes to the public state education system in Valparaiso, 137 km (85 miles) northwest of Santiago June 5, 2006. REUTERS/Eliseo Fernandez REUTERS/Eliseo Fernandez

You are mad with your mother. And also mad with yourself for being mad. But at what point did your face tighten up into this angry snarl? A while ago?

Yes, some time ago. When humans began to evolve, in fact.

Researchers at UC Santa Barbara and Griffith University in Australia, according to the journal, Evolution and Human Behavior, said that everyone has the same angry face: tight lips, frown, puckered brows. Even if you are blind and have never seen an angry face, you will get it soon. Look into the mirror and check it out first!

According to Science Daily, "Our earlier research showed that anger evolved to motivate effective bargaining behavior during conflicts of interest," 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 Center for Evolutionary Psychology.

Each part has been tested and experimented upon by the team----beginning with the lowered brows, and going on to raised cheeks, pursed lips, raised mouth, dilated nose and expanded chin. It is easy to see what makes someone angry: it is a "threat display." Even animals tend to do it. Look at how a frog expands itself, or how a dog shows its fangs in order to look bigger and stronger.

Strong persons get angry fast, so that they can fight and win conflicts in their favour. "Seven distinct muscle groups" contract quickly. Strangely, if someone inflicts harm on others, he or she can strike a better deal. Being a "bargaining emotion", the best way to control it is to let on to everyone that the anger-triggering event is not acceptable, and both parties need to arrive at an agreement. Anger puts a face to its feeling. However, it's not just how it looks, but what it means. As Science Daily

quotes Sell: "Each element is designed to help intimidate others by making the angry individual appear more capable of delivering harm if not appeased."

The upper body is more threatening, so the face becomes the index of strength. Evolution chose this method to show anger, because the face assumes the shape and size of the threat. Every part of the face is messaging anger.

So don't worry---you aren't unique about getting angry, at least!