At first I thought it was satire, but it's real:
http://www.heraldextra.com/news/local/education/college/byu/byu-researchers-find-free-textbooks-are-just-as-effective-as/article_5f3fbc35-404c-51f3-bbe7-68907de208fd.html

I guess it's good that they're finally getting around to applying the scientific method to figure this one out...