Until recently, though, scientists had not considered whether a substance that promotes cuddliness and warm, intimate bonding might also play a role in competitive sports.But the idea makes sense, says Gert-Jan Pepping, a researcher at the Center for Human Movement Sciences at the University of Groningen in The Netherlands, and the author of a new review of oxytocin and competition. "Being part of a team involves emotions, as for instance when a team scores, and these emotions are associated with brain chemicals."In the shootouts, he says, each player almost certainly had experienced a shared burst of oxytocin, and in the rush of positive feeling, had shot better.

More telling, in a study presented last month at the annual meeting of the Society for Neuroscience in New Orleans, male prairie voles that exercised by running on wheels over six weeks displayed changes in their nervous systems related to increased oxytocin production and bonded rapidly and sturdily with new female cage cohabitants, while unexercised males showed little interest in any particular mate."Lots of stresses can trigger oxytocin release, among them exercise," says William Kenkel, a doctoral candidate at the University of Illinois at Chicago, who led the study. He continued that "it stands to reason, then," that such exercise-related oxytocin release "could facilitate social bonding."Athletes, by the way, aren't the only group affected by oxytocin in a sports setting, "Sports fans, too, experience spurts of oxytocin release," Dr. Pepping says, including the half-hearted. "Even when you don't much like sports," he says, watching others high-five and leap about the living room after their favored team scores will lead "your body to release oxytocin." At that moment, we are all a fervent Bears or Giants or Oklahoma City Thunder fan, whatever we might think, in our more sober moments, about that James Harden trade.