According to a new study by researchers at the Annenberg School for Communication at the University of Pennsylvania, both Democrats and Republicans significantly underestimate the diversity of policy attitudes within their own party and among the opposing party. According to a new study by researchers at the Annenberg School for Communication at the University of Pennsylvania, both Democrats and Republicans significantly underestimate the diversity of policy attitudes within their own party and among the opposing party. Political science Phys.org – latest science and technology news stories