AP Photo/Ben Margot
In this Aug. 20, 2011 photo, football fans fight in the stands during a preseason NFL football game between the San Francisco 49ers and the Oakland Raiders in San Francisco. After two men were shot and wounded following the preseason game, the NFL and the mayors of the two cities jointly called for an end to "intimidation" and acts of violence at sporting events.
What is it about sports that compels fans to get so heated that it can sometimes lead to violence? Rick Grieve, professor of psychology at Western Kentucky University, joins the show to explain theories on why sports rivalries can turn violent.