OVER MILLIONS OF YEARS, MAN HAS EVOLVED TO THROW PUNCHES, TO TAKE THEM—AND TO BE FASCINATED BY THEM. THAT'S ESPECIALLY TRUE WHEN THEY POP UP IN PLACES THEY AREN'T SUPPOSED TO BE. AND THERE'S GOOD REASON WHY WE CAN'T LOOK AWAY

Compared to other mammals, the great apes are an aggressive and violent group of primates, and among the great apes the case can be made that we are the most violent.

—DAVID CARRIER, University of Utah Biologist

Every time I land a punch, it's satisfying.... It's not just, Oh, I hurt someone. It's like an instant gratification, a bit of an accomplishment.

—HOLLY HOLM, UFC Champion, on ESPN Radio

IF the eyes are windows to the soul, then a punch to the face is a baseball crashing through the glass. Even before Holm landed 29 "significant strikes" to the head of Ronda Rousey in the stunning UFC women's bantamweight title upset in November, there was a punching revolution under way at the top levels of MMA, with leather throwers such as Conor McGregor and Robbie Lawler slowly supplanting the army of jujitsu artists that once owned all the belts.

In noncombat sports, meanwhile, swinging one's fist at the countenance of another—landing it near any of the seven holes in the human head—is banned in football, baseball and basketball. Soccer, too. Yet despite these prohibitions, the punch, the only offensive move allowed in boxing, remains popular among athletes outside the ring. And outside the locker room. And, as in Blake Griffin's recent encounter with a Clippers equipment manager, both inside and outside the restaurant.

The stakes are heightened for both the untrained puncher and punchee in such instances. Broken jaws and cracked metacarpals are more common in street fights than in MMA matches, which goes a long way toward explaining why—except in that infamous outlier, hockey—throwing a George Foreman at someone's grill is penalized so severely in the games that forbid it. Even if many of those punishments land with less accuracy than the punches that spurred them.

A worthwhile analysis of what some fans call "extracurriculars" must meld physiology, psychology and ethics, and like athletic competition itself, that study stands to reveal as much about human nature as it does about athletes in particular. All of the different strains of intrasport pugilism are available for study on YouTube, which loops examples together, end to end, for our edification and enjoyment. There's a helmetless Dez Bryant's getting popped in the mouth last summer at training camp by a Rams cornerback named Imoan Claiborne. There's Nebraska cornerback Kellen Huston laying out a jubilant Missouri fan after the Tigers upset the Huskers in 2003. After a brief ad, you are treated to J.R. Smith landing a Bruce Lee backfist to the face of Jae Crowder in last year's NBA playoffs—a shot that not only knocked out the Celtics' forward for a few seconds but also tore his ACL.

There have been justifiable punches over the years—such as those thrown by Syracuse football players after their opponents from Texas allegedly aimed racial slurs at black players in the 1960 Cotton Bowl—and there have been bizarre swarms of them, as when Georgetown's basketball team accompanied Vice President Joe Biden on what was ostensibly a feel-good visit to China in 2011, only to have their exhibition game against the Bayi Rockets devolve into an interteam street fight.

Heroes as saintly as Bill Bradley, Roger Staubach and Steve Kerr have succumbed to the urge to mash someone else's face in. (Respectively, the faces of Rick Barry, Clint Longley—who picked two fights with Staubach during the Cowboys' 1976 training camp—and a certain Bulls two guard.) "I knew I had two choices," Kerr told SI in '97 about what he felt were Michael Jordan's excessive shoves during a scrimmage. "Either let it go and be obedient to Michael forever, or fight and probably get my ass kicked." The black eye Kerr sported the next day indicated that the latter had come to pass, but his pride and his rep remained intact—the underlying goal of most one-on-one rumbles.

Within these disparate scenarios, three main causes of punching stand out, each of them rooted in a perceived lack of respect felt by the puncher before he lets his fist fly. The athlete who punches is almost always seeking to uphold his honor in some way, his fury and internal chemistry blinding him to the fact that throwing hands usually accomplishes the opposite.

There is the onlooker to consider too. While researching this article, its author found himself both riveted and disgusted by the dozens of sports punches brought forth with a single keystroke. Why are we so captivated? What fascinates us about the moments just before and after a fist meets a face? Why do we humans tend to gather 'round—or at least take a quick peek—anytime a fight breaks out in our midst?

Instead of asking why we punch each other in the face, argues anthropology professor David Puts of Penn State, "the better question is, What do we get really angry about? The research tells us that threats to social status among peers is a big one. If you're made to look bad in front of other guys or in front of a female, that's a threat to your access to mates. It can flip a switch in us."

University of Utah biologist David Carrier almost came to blows with another academic not long ago over something as innocent as Carrier's belief that the foreheads of sperm whales were evolutionary adaptations intended to batter other sperm whales during mating fights. "He was getting frustrated and angry, waving his fist in my face," Carrier says of his colleague. "He said, 'I can punch you with this, but that doesn't mean that's why it evolved!' That's when I thought, Maybe that is why the fist evolved."

Summarizing the seven years of research that followed, Carrier says, "Humans are the only animals capable of forming a fist. See how the fingertips fold into the center of the palm? Apes can't do that. Their fingers are too long and their thumbs are too short." These self-contained, transformable clubs at the ends of our arms are why, according to Carrier, humans slug each other while our evolutionary forebears likely preferred more superficial assaults such as slapping, scratching and hair-pulling.

Carrier's conclusion is as blunt as a right from Mike Tyson: "We are face-punchers."

1 THE DON'T-DISS-ME (OR I'M-NO-PUNK) PUNCH

Puts's assertion that losing face in front of others is a main cause of fisticuffs may have been supported in the petri dish of the Jets' locker room last August when defensive end IK Enemkpali once more asked quarterback Geno Smith when Enemkpali might be reimbursed the $600 he paid to fly Smith to Enemkpali's youth football camp in Texas one month earlier. Smith had not shown up for the camp, which had embarrassed Enemkpali in his hometown of Pflugerville—and, if we judge by the result, threatened the defensive end's social status. While Smith allegedly ducked the issue (though he has denied owing Enemkpali money), other Jets players had ribbed Enemkpali for letting the QB get one over on him. At the Jets' facility on the morning of Aug. 11, a 260-pound member of the only species that can form a fist formed one and threw it.

Smith's broken jaw had to be surgically repaired, which, aside from rearranging the Jets' QB depth chart, defied the additional findings of Carrier and his research partner, Dr. Michael Morgan (an ER surgeon and a black belt). They found that the parts of the face that break most frequently in fights have become thicker and stronger since our ancestors rose from all fours and began standing. And punching.

"The jaw is one of the most frequently broken bones in a fight," Carrier says. "Imagine breaking your jaw even 500 years ago, how debilitating it would be. Now go back millions of years. If you broke your jaw, you'd probably die. You couldn't eat." Thus the mandibles, eye orbits and cheekbones of survival-hungry early hominids became more durable.

With apologies to Holm and the extra helpings of glove leather she served to Rousey, the skulls of women, who have engaged in far less mug-socking over the millennia, do not demonstrate this same toughening. And, Carrier adds, "the muscles with the greatest sexual dimorphism" (that is, those with the largest differences in strength between the sexes) "are the muscles of the neck. If your muscles there aren't very strong or aren't turned on in time, they can't protect you. Which is also why sucker punches are so dangerous." Which leads us to ...

2 THE SUCKER PUNCH

Carrier is asked to view a clip from a December basketball game in which BYU guard Nick Emery, jogging under the basket during an offensive set, planted his foot and swung his left fist—straight-elbow molly-wop style—at the face of unsuspecting Utah guard Brandon Taylor. Carrier, who rarely watches basketball, responded to the video not as an evolutionary biologist but as a man. "My first reaction is that the player who got punched was incredibly calm," he said with a chuckle. "I expected him to explode off the floor in a rage and go after the guy. Because that's the kind of punch where you expect [the punchee] to come after you with complete reckless abandon."

Emery's punch that night seems to have affected Taylor less than it has the millions of screen-gazers who have seen it. When the referees and 15,000 fans (via jumbotron) reviewed the punch, the crowd let out an outraged howl and the refs called a flagrant 2 foul and ejected Emery. Taylor played the last 1:44 of the Utes' 83--75 win, looking none the worse for wear.

In the heady days that followed, though, there were calls for Emery to be suspended for the rest of the season, kicked off the team, kicked out of school. Utah coach Larry Krystkowiak canceled next season's BYU game—halting a series that had been played 257 times over 107 years—explaining, "I am concerned about the potential for serious injury in the current atmosphere of this rivalry." Any pretense of collegiality between the two camps dissolved when BYU athletic director Tom Holmoe threw a roundhouse via Twitter ("Canceling the [game] is RIDICULOUS") after which a BYU staffer, thinking the boss's account had been hacked, deleted the tweet. Holmoe retyped it and tweeted it again.

Emery's punch provoked this string of harsh reactions, says professor Jonathan Gottschall of Washington & Jefferson College, "because it exemplifies what I call cowardly violence. In other words, there is the intent to do harm without putting yourself in danger."

Gottschall is the author of The Professor in the Cage, a riveting first-person account of the three years that the 40ish, physically unimposing English teacher trained to become an MMA fighter. "A punch like that violates our codes of ethics," says Gottschall. "We consider guys [who throw sucker punches] to be scoundrels without honor. When men compete, even when men fight, there are unspoken but very clear rules. It's a code that runs deeper than our culture. It's in our DNA."

Which explains why Puts, namesake of Penn State's Puts Lab and one of the world's most esteemed experts in human behavior, responded to his viewing of Emery's punch by exclaiming, "What a d---!"

3 THE DON'T-MESS-WITH-MY-TEAMMATE PUNCH

Perhaps the most infamous punch ever thrown in a nonfighting sport is the straight right by Lakers forward Kermit Washington to the face of Rockets forward Rudy Tomjanovich on Dec. 9, 1977. It was not a sucker punch but a terrible accident of time, space and circumstance that not only changed both men deeply but also added a third referee to all NBA games and dramatically increased the league's penalties for fighting.

It happened in the third quarter of a close, otherwise unremarkable game, right after Lakers center Kareem Abdul-Jabbar took issue with a shove from Houston big man Kevin Kunnert. The 6'8", 222-pound Washington, in his role as team enforcer—a role as common in the disco-era NBA as it's ever been in the NHL—confronted Kunnert so that Abdul-Jabbar, the league's best player, could keep his hands clean. (Abdul-Jabbar had broken his hand, and been fined $5,000, when he socked Bucks rookie Kent Benson in the eye seven weeks earlier.)

Before Washington and Kunnert could get into it, Washington sensed a red blur approaching him from behind. It was Tomjanovich, running in to make peace. But Washington didn't discern the "make peace" part in time to keep from throwing the punch that caved Tomjanovich's face in and sent him flying backward like a cartoon character.

Several witnesses inside the Forum that night would later tell author John Feinstein (for his 2002 book The Punch) that the sound of the blow is what has lingered with them ever since. Abdul-Jabbar called it a "crack, like a melon landing on concrete. It's twenty-four years ago, but I can still hear it." Rockets guard Calvin Murphy "cried at length," Feinstein wrote, while discussing the moment. Jerry West, the Lakers' coach at the time, called the punch "one of the reasons I got out of coaching."

Tomjanovich, then a four-time All-Star, would not play again for 10 months. When he returned, he was not quite the player he'd been before the punch, and his face, which would undergo five surgeries, looked structurally different: longer from nose to chin, with a noticeable loss of symmetry. The NBA suspended Washington for 60 days and fined him $10,000, double Abdul-Jabbar's short-lived league record. A jury would later award Tomjanovich $3.3 million in damages from the Lakers, a massive amount for that era and $500,000 more than Tomjanovich had asked for. (The case was eventually settled for $2 million.)

The punch's second-greatest impact was on Washington, who before the incident had been regarded as a gentle giant but after it spent decades trying to prove to the world that he was not what that moment implied he was. Washington did not proclaim that intent; rather, he infused it into his numerous charity missions to Africa, his public-minded business endeavors and countless community-service projects. His obsession with this penance would eventually cost the former academic All-America his career and damage his marriage, his finances and his peace of mind.

Like Washington, Nick Emery and IK Enemkpali each had violent incidents in their pasts before throwing the punches that overshadowed everything else in their careers. At Louisiana Tech, Enemkpali scrapped with a bouncer who was also an off-duty policeman. At Lone Peak High in Highland, Utah, Emery was ejected in the third quarter of a rare loss for clotheslining an opposing point guard and flinging him into the air by his neck. Emery's high school coach, Quincy Lewis, once called his star guard "just an ornery dude on the court."

BYU declined requests from SI to interview Emery, Cougars coach Dave Rose and Lewis, who is now one of Rose's assistants. But during an interview with a TV station when he was at Lone Peak, young Emery explained, "When I get into a game, I just flip—I'm honestly one of the meanest players. I feel bad sometimes and I'm just like, Gosh, why did I do that?"

Four possible influences—Emery's own subpar play, rivalry games, road crowds and losing—seem to have something to do with it. Before punching Utah's Taylor, Emery shot 3 for 15 and was beaten by Taylor off the dribble at least eight times. Taylor, when asked recently what Emery had yelled at him following the punch, said, "He looked down and was like, 'Stay the f--- down, b----!'"

Which only makes it more astonishing that Taylor did not rise and retaliate. A native of Los Angeles who had seen fisticuffs on basketball courts before, Taylor, a psychology major, says, "What am I gonna do? Get thrown out of the game? Teach that lesson to my teammates? I'm a senior. He didn't hurt me. It didn't get under my skin."

Too often we judge backing down from a fight to be unmanly. But Gottschall reminds us that when Alexander Hamilton was challenged to a duel by Aaron Burr in 1804, Hamilton couldn't bear to be seen as cowardly, so he showed up at the arranged place and time, and was killed. As one of Hamilton's friends wrote after his death, "If we were truly brave, we should not accept a challenge, but we are all cowards."

BYU may well let months pass before allowing Emery to explain his side of things beyond the prepared statement issued after the incident. ("I got caught up in the intensity of the game and let my emotions get the best of me.... ") That's how long BYU athletics waited in the case of Kai Nacua, the safety whose punching rampage 15 months ago provided perfect examples of both dishonorable violence and noble comeuppance.

BYU had just lost a testy double-overtime heartbreaker to Memphis in the 2014 Miami Beach Bowl when a donnybrook broke out near midfield and Nacua, a 6'2", 213-pound sophomore who had started and played the whole game, sprinted into the fracas and threw a hook at an unsuspecting Memphis player. Unfortunately for Nacua, a Memphis defensive end named Isadore Outing, who hadn't touched anyone (yet), witnessed Nacua's sucker punch from two steps away, then calmly closed those two steps and, looking Nacua squarely in the eye, threw what might be the closest approximation of the Kermit Washington punch that sports had seen in nearly 40 years.

The result was not nearly as catastrophic, fortunately. Outing's fist ripped a gash in Nacua's cheek that made him look like he'd been hit by a ripe tomato, but Nacua stood right back up and, possibly fueled by vengeance or a perceived threat to his social standing, took a running start and threw another sucker punch at the turned head of a Tigers tight end. This is the one you may have seen in Vine form (6 million loops and counting): number 12 in a BYU jersey leaping, Crouching Tiger, Hidden Dragon style, toward his victim and challenging the guy's neck muscles to keep his head attached. When Nacua landed and danced away from the scrum, he didn't look angry. He looked puzzled.

Nine months later he explained to The Salt Lake Tribune, "It was the worst feeling ever.... Immediately I was accepting [of the punishment, a one-game suspension]. I was just humbled. Everyone saw what happened. There is no trying to fight it, because it was all over TV."

Nacua served his one-game suspension and performed 100 hours of community service. He returned to the field against Boise State in the Cougars' second game last fall, snagging a school-record three interceptions in a 35--24 win.

As shallow as our understanding of punches is, our failure to consistently police their invasion of sports is even more, well, striking. Nacua's and Emery's one-game sitdowns seem light punishment compared with, for instance, the seasonlong suspension of Oregon back LeGarrette Blount after he socked Boise State's Byron Hout in the jaw in September 2009. Blount's punch was provoked, although not justified, by Hout's verbal taunt a moment before. (Blount had promised an "ass whuppin'" of Boise State but instead had rushed for minus-five yards in a humbling 19--8 loss. Hout ran up to him after the game, slapped him on the shoulder pad and said, "How 'bout that ass whuppin'?"—at which point Blount fired a jab that crumpled Hout to the blue turf.)

Hout got up after Blount's punch—no harm done—but Blount still lost most of his senior year to suspension. Enemkpali and Smith, on the other hand, seem to have paid for their punch evenly: Smith suffered his physical injury and subsequent demotion, and Enemkpali is now considered, in some quarters, a locker-room cancer and sucker puncher. The Jets declined a request to interview Smith, whose jaw injury made Ryan Fitzpatrick the Jets' starting quarterback, but we can safely assume that the avalanche of public reaction that the young quarterback endured long afterward—about Enemkpali's punch lifting the Jets to their surprising winning season, about Enemkpali being the team's unofficial 2015 MVP—inflicted some nonphysical pain. In September, Smith told Newsday, "Emotionally, it's tough ... but I've been getting good support in the locker room with the guys." Smith joked about the weight he'd lost due to his injury. "Sometimes when I walk past a mirror, I'm like, 'Wow, I look skinny today!'" he said.

The rest of us might benefit from a different sort of look in the mirror, to determine the reasons behind our craving for the addictive pulse-jump that accompanies fistic violence, our eagerness to judge how people handle themselves when push comes to punch. Like prehistoric spectators before us, we are hooked on watching one man emerge dominant over another.

"Part of what draws us to it," says Gottschall, "is that it's so tragic. One guy has his arm up [in triumph] while the other guy has had something taken away from him in the most public manner possible."

Some social scientists, Gottschall writes, argue that "our attraction to violent spectacles was good for us.... I will argue for a more pessimistic position: We are drawn to violent entertainment simply because we like it. We are not nearly as good or as civilized as we think."

SEVERAL WITNESSES WOULD SAY THE SOUND OF THE BLOW IS WHAT HAS LINGERED WITH THEM. ABDUL-JABBAR CALLED IT A "CRACK, LIKE A MELON LANDING ON CONCRETE. IT'S TWENTY-FOR YEARS AGO, BUT I CAN STILL HEAR IT."

"IT'S A CODE THAT RUNS DEEPER THAN OUR CULTURE," SAYS GOTTSCHALL. "IT'S IN OUR DNA."

AS ONE OF ALEXANDER HAMILTON'S FRIENDS WROTE, "IF WE WERE TRULY BRAVE, WE SHOULD NOT ACCEPT A CHALLENGE, BUT WE ARE ALL COWARDS."

PHOTOPhotograph by Erick W. Rasco for Sports Illustrated PHOTOAP PHOTODOWN AND OUT Washington slugged Tomjanovich on pure instinct, an impulse that would haunt both men for years; when Emery (below) punched Taylor, the results were fortunately less damaging. PHOTOROBERT STRAUSS FOR SPORTS ILLUSTRATED (TOMJANOVICH)[See caption above] PHOTOGENE SWEENEY JR./GETTY IMAGES (EMERY)[See caption above] PHOTOPHIL NOBLE/REUTERS (FRANCIS)FACE IT Humans are the only animal capable of making a fist—and so men's faces have evolved to withstand a punch, as boxers and MMA fighters often demonstrate. (Women's faces, however, evolved differently.) 1 Dean Francis, 2007 2 Anthony Pietrantonio, 2011 3 Glen Johnson, 2011 4 Ronda Rousey, 2015 PHOTOMATHIEU BELANGER/REUTERS (JOHNSON)[See caption above] PHOTOCHRIS TROTMAN/GETTY IMAGES (PIETRANTONIO)[See caption above] PHOTOQUINN ROONEY/GETTY IMAGES (ROUSEY)[See caption above] PHOTONEW YORK DAILY NEWSJET DEBT When Enemkpali clocked Smith over money allegedly owed, it sent the latter to the injured reserve list while the former landed in Buffalo. THREE PHOTOS

HOLE YARDS PAR R1 R2 R3 R4
OUT
HOLE YARDS PAR R1 R2 R3 R4
IN
Eagle (-2)
Birdie (-1)
Bogey (+1)
Double Bogey (+2)