22 July 2002



 Watching Fights Makes Fish More Feisty


  BLOOMINGTON, INDIANA--Could watching Lennox Lewis knock out Mike Tyson make you more likely to win a boxing match of your own? Don't count on it, but a study of aquarium action suggests that watching combat certainly pumps up fish.

To examine the effect of watching fights on fight outcomes, behavioral ecologist Ethan Clotfelter of Providence College in Rhode Island set up fights between pairs of male Siamese fighting fish (Betta splendens). A third fish watched the fight and then entered the tank against a similarly sized opponent that hadn't seen a fight. Although the two were evenly matched physically, the fish that had watched a fight triumphed 80% of the time. There was no effect if spectators had watched two males separated by a barrier that kept the peace.

Previous research has shown that watching fish clash raises levels of hormones such as testosterone, and other studies have shown that higher levels of testosterone make fish more likely to fight. But Clotfelter's study, presented here 16 July at the annual meeting of the Animal Behavior Society, is the first to show that watching aggression makes fish more likely to win their next fight. Like the fish, people start to swim in hormones when they watch a fight, Clotfelter says, and he thinks his latest findings might apply to humans as well.

Lee Dugatkin, a behavioral ecologist at the University of Louisville in Kentucky, agrees. "If you look at the crime rates after a big soccer match, they actually rise because you're raising aggressive hormones, particularly in males." Men who have watched a contest are certainly more likely to get into a fight, he says, and "they'd probably be more likely to win."

Clotfelter plans to investigate whether the quality of the fight being watched has an effect as well. Perhaps the length of the fight is important, he wonders, or maybe watching a match with a decisive knockout would have a more potent effect than a draw.


Related sites
Ethan Clotfelter's Web page
Lee Dugatkin's Web page
Animal Behavior Society
International Betta Congress


 © 2001 by the American Association for the Advancement of Science.