Are you a Giants fan? Are you feeling good today? It could be the testosterone boost you got from vicariously participating in the Giants' miraculous late-game win in Sunday's Super Bowl. This effect has been known about for quite some time -- a 1998 paper by University of Utah researchers Berhardt et al. demonstrated that beyond its effects on mood and self esteem, watching your team win not only boosts your testosterone level, but also decreases the levels of circulating testosterone in the fans of the losing team. Because testosterone, long linked to violence, now appears to have much more to do with social dominance -- here's an article I wrote on the subject last year -- it's hardly surprising that these changes in hormone levels can affect not only a fan's post game euphoria (or depression) but also their future behavior. Indeed, competitors who lose a contest and subsequently experience a drop in their testosterone levels are less likely to challenge their foe again, according to a paper in the December 2006 issue of Hormones and Behavior, by Robert Josephs and Pranjal Mehta. All of this should remind students of the work of Robert Sapolsky, who studies social dominance hierarchies in troops of baboons, of the ways in which tests of strength and / or fighting ability help determine pecking orders in everything from crayfish to humans. originally posted at 60 Second Science -- Edited by christopher.mims at 02/04/2008 3:15 PM