The most feared jaws in football have again snapped shut on human flesh. Renowned Uruguayan jerk Luis Suárez appeared to chomp the shoulder of Italy's Giorgio Chiellini during a World Cup match on Tuesday. The player's latest chomp raises questions about sportsmanship. Namely, what kind of brain decides it is OK, in the course of athletic performance, to seize part of a competitor's body between your teeth like a rabid pit bull?

The psychology of poor sportsmanship is something that generally comes up in the context of child athletes. Acting out on the field can be a sign that a kid doesn't handle competition well, or hasn't yet developed the cortical means to regulate his feelings. By the time you are a grown adult and a professional football player, though, athletic misbehaviour signals something else besides one's presence at a way station on the path to moral maturity.

In adults who aren't world class athletes, poor sportsmanship might indicate an anger issue like intermittent explosive disorder, or any condition-autism, ADHD-that impairs your understanding of social norms. Or you could just be a jerk.

But according to Dr. Richard D. Ginsburg, a clinical psychologist and sports psychology consultant for Massachusetts General Hospital, the tantrums of professional players are often made of stronger stuff. "You have athletes who are highly driven to win, fiercely competitive, and who must increase their intensity in ways that involve physical contact with others," he says. And because they are doing all this in situations-like a World Cup match-that are highly visible and drenched with meaning, the adrenaline generated is tremendous. "An intense amount of arousal is required," Ginsburg says. "It's the moment. The media exposure. Learning how to harness your aggression in a way that's effective and balanced is an art form for pro athletes. People don't appreciate how hard it is."

Ginsburg, who has never met or treated Suárez, told me he was reluctant to make assumptions about the footballer's character in particular. But as a general rule, he says that putting a player with poor impulse control in such a hypercharged context is like sprinkling your fireplace with gunpowder. "It's the situation and it's also who we're dealing with," he says. "These huge emotional outbursts can start to make a kind of sense."

Bad sportsmanship occasionally pays off, as when a player might hypothetically handle the ball off the line in a World Cup match against, say, Ghana. But Ginsburg notes that it would be hard to argue that Suárez's more tooth-focused behaviour was somehow strategic. Though he wasn't penalized for his light Italian snack, FIFA could choose to ban Suárez for the rest of the tournament.

Back in April 2013, when Suárez tenderized the arm of Chelsea's Branislav Ivanovic, sports psychologist Dr. Thomas Fawcett echoed this interpretation, speculating that we'd witnessed something "primitive" and "spontaneous." He told the BBC that biting usually signalled frustration and that he suspected Suárez would bite again. Good call, Dr. Fawcett! Give that man a raise.