“Animal species have ritualistic dominance behavior to establish territory or status between males. It is ritualistic, stylized, and designed to limit injury to the participants.
The human equivalent is the monkey dance. It is not just the fistfight you might imagine, but all of the steps leading up to the fight.
It begins with a hard stare, which is followed by a verbal challenge (often, "What are you lookin' at?"). The verbal back and forth can go on for some time, or the ritual can be ended with an apology and submissive body language.
If the dance is not ended, one or both of the participants will close the distance. It is completely subconscious, but most will "puff up," trying to look bigger, spreading their chest muscles and coming up on their toes. Sometimes they bob up and down like roosters. The verbal interplay continues.
Once they have closed distance, an apology still works. If one backs down, then dominance is established and the monkey dance is over. What both parties are actually hoping for is that friends will intervene and pull them apart. If that happens, dominance isn't established per se, but both have established their willingness to defend status and territory. They can then coexist in the same space with mutual respect.
If they are not separated and neither backs down, the next stage is contact. It will usually be a two-handed push to the chest or an index finger poke to the chest. In some cultures you knock the hat off. In almost any culture, if the contact is poking his nose with your index finger, the fight is on.
The next step is the fight, but it isn't a very skilled fight. It is usually a series of looping punches aimed at the top and side of the head — exactly the kind of thing more likely to damage the hand of the person punching than the person being punched.
One of the keys to understanding that this is a script is that even trained fighters fall into this pattern, knowing full well (with their human brains) that it is a stupid way to fight.
Robert Twigger, in his book Angry White Pyjamas, describes the senior-most instructors of Yoshinkan Aikido on an epic pub crawl after the death of their founder. By the end of the night, these masters of aikido wound up in a brawl — throwing wild punches and rolling around on the floor. These weren't just dojo ballerinas. These were the men responsible for teaching the Tokyo riot police.”
Rory Miller, Conflict Communication