Law professor Ian Ayres did a study once showing that car salesmen tend to drive tougher bargains with black shoppers than with white shoppers. Malcolm Gladwell explained in Blink that this was only because the car salesmen didn't realize they were being prejudiced, and would stop as soon as they read Blink and realize they are leaving money on the table. Judge Posner and I disagreed, arguing that, in our experience, car salesmen were more cynical than Gladwell assumes. The good folks at Cars.com just spent $3.5 million to buy 30 seconds of Super Bowl air time to settle this long running argument by showing us what car salesmen see when they look at black shoppers.