Last night was the first time I nearly got into a fight since... probably elementary school. Some dude and I were walking past each other in a not-so-crowded night club, and he bumped me with his shoulder. Not a body-check, but enough for me to have to respond -- you never let another guy touch you without touching back. That tells him that he was wrong in assuming you were lower than him in the pecking order, and it usually ends there -- "Oh hey, my bad."
Because it was an above-normal shoulder bump, though, I gave him a good shove with my elbow in his lower-mid back. Both of us realized that these were a little uncalled for, but once the provocation starts, it's hard to stop it -- the reason that insults used to be considered crimes before the rise of centralized states and police forces. A typical misunderstanding in a tavern used to easily escalate into a heat-of-the-moment murder.
Now we've both turned around to face each other and size one another up. He was about 3 inches taller than me, probably 40 - 50 pounds heavier, mesomorphic shape, and probably 5 - 8 years younger. He was South Asian, almost certainly a foreign student, since he had his shirt unbuttoned to show chest hair and gold jewelry, and had chin-length curly hair. So, he surely came from a place with a stronger "culture of honor" than most people I see in clubs. (Of course, being half Scotch-Irish hillbilly, I've got the "you're stepping on the wrong man's dick" genes too.)
Most conflicts like this in the animal world are not settled by an all-out brawl. The two try to signal to each other about where they score on all of the traits relevant to winning a fight: muscularity, size, energy level, speed, and so on. This benefits both of them since they can walk away if they're evenly matched, rather than get locked into a wasteful war of atrition. For example, the behavior of stotting displays the health of the prey animal, which tells the predator that it would pay off more to pursue some other individual -- "I'm too vigorous for you to catch, so don't even bother." It may also be an example of the handicap principle: "Only a super-fit animal like me would slow down and bait you into approaching me." See some springboks stotting here.
If fights between humans depended only on sheer strength, we would only signal who was stronger, and there's a very clear way to tell -- who is more muscular? If there were any asymmetry in muscle mass, the two could easily tell, and either the less muscular guy would not start shit in the first place, or if he did, the more muscular guy would always escalate the fight and beat him up.
But we're not that simple: as long as he has some muscle tone, a much leaner guy can win a fight if he's quick, high-energy, and uses explosive moves. Think of Brazilian mixed martial arts fighter Anderson Silva, who can knock out any tank-shaped, Neanderthal-skulled wrestler, and who often shows off his dancing skill. It's probably no accident that sub-Saharan Africans excel in both dancing and beating people up, compared to Europeans or East Asians.
And it's just like MMA in a night club, bar, or wherever -- since there are no rules, the agile, explosive guy can knock out a big galoot. With the energy high I was on, and having warmed up long before and already gotten into high gear, I could have easily jumped and planted my knees in that guy's gut 10 times in under 5 seconds. Shit, I could have climbed the walls if I wanted to. To signal this to him, I simply showed off my dancing skills, moving my whole body, taking up a lot of space, and making explosive moves with my limbs. Luckily, "Thriller" had just come on, so it was simple to get into the groove here.
He was very pissed off and stared at me for the better part of the song, and was talking to his buddy as well. Again, if sheer strength were all that mattered, he would've quickly moved in and started a fight. But by displaying my own physical prowess, albeit of a different type than his, as well as signaling emotional coolness (with a confident smile) and high status (by taking up lots of space without being encroached on), I shut him down.
I also wonder if odor plays a role. A recent study showed that men's underarm smell ("stress related odor") is harder to disguise than women's, and that women's noses are much more difficult to fool than men's when researchers try to mask the smell. I have a hyper-sensitive sense of taste and smell, so much so that I can perceive how the percent of girls who are ovulating changes from week to week in dance clubs. Perhaps when that guy bumped into me, I smelled that he was afraid and wouldn't escalate, so that I could shove him pretty hard and not suffer any consequences, as well as not run away and even bait him into coming up to me by leaving my torso area wide open and undefended while dancing.
It's not that I'm foolhardy -- last week, a group of guys had gotten into a fight outside the same club, and one -- who weighed over 250 pounds and looked like a serial killer -- gave me a good shoulder bump, but I let it go that time because my gut reflex was that I wouldn't even be able to respond with a strong, solid series of pats on his shoulder. (There were also lots of security guards nearby.) Still, most of the time when some guy tries something like that, I respond in kind and nothing happens, despite the other guy almost always being taller, bigger, or more muscular. Maybe I can smell who is a real badass and avoid them, and who is just pretending and respond with impunity.
It may seem strange that men have not evolved stronger noses, since they'd profit much more greatly by being able to smell fear. But the trouble is that our sense of smell isn't very good, so we have to be very close up -- and aside from the cases where someone bumps into you, you're probably going to be far enough apart while sizing each other up that you can't rely much on smelling fear.
Given how rare it is for me to not do something back, I conclude that most guys who act tough by trying to start shit are actually insecure pussies. They're losers, at the bottom of the social ladder, and are merely making some desperate, last-ditch attempt to look powerful in public, much like muggers or other petty criminals.