What divides us, it turns out, isn't the issues. It's the social and political contexts that color how we see the issues. Take nuclear power, for example. In the U.S., we argue about it; in France, the public couldn't care less. (The U.S.'s power is about 20 percent nuclear; France's is 78 percent.) Look at nearly any science issue and nations hold different opinions. We fight about gun control, climate change, and HPV vaccination. In Europe, these controversies don't hold a candle to debates about GMO foods and mad cow disease. Scientific subjects become politically polarized because the public interprets even the most rigorously assembled facts based on the beliefs of their social groups, says Dan Kahan, a Yale professor of law and psychology who ran the 2011 science-expert study.