But the financial evidence for racial discrimination in the NBA has since diminished. And there's plenty of bias in professional sports that's both more pervasive and more pronounced than racial discrimination. The home-court advantage, for example, seems to stem in part from referees who are biased toward the home team. Much of the research in this area has focused on soccer referees, who tend to assign more injury time at the end of a game when the home team is losing and less when it's ahead. They also give out fewer red and yellow cards to the home team and make fewer calls in the lab when watching video with the crowd noise turned off. As a general rule, the bigger the crowd, the bigger the bias.
There are more surprising sources of bias, too. In 1988, a pair of social psychologists from Cornell named Mark Frank and Thomas Gilovich published a study on "Black Uniforms and Aggression in Professional Sports" (PDF). They looked at data from hockey and football and found there was a connection between the color of a team jersey and the number of fouls called on the player wearing that jersey. The teams that wore black (or near-black) tallied a disproportionate total of penalty yards or penalty minutes between 1970 and 1986. (In football, these black-shirts included the Raiders, Steelers, Bengals, Saints, and Bears; in hockey, the Flyers, Penguins, Canucks, Bruins, and Blackhawks.) Meanwhile, the teams wearing the most gentle colors—like the aqua-coral-and-white Miami Dolphins—seemed to get the fewest whistles.
It's possible that the owners of black-shirted teams tend to hire more aggressive players. But Frank and Gilovich found that the pattern held even when teams switched colors midseason. The Pittsburgh Penguins swapped their blue uniforms for black ones in the middle of the 1979-80 campaign, in solidarity with the hometown Steelers, who had just won Super Bowl XIV. The team logged 50 percent more penalty minutes after the change than they did before.
In the lab, Frank and Gilovich demonstrated that football referees were more likely to call a penalty on a player wearing black than one wearing white or grey, even on an identical play. This could be a weird offshoot of racial bias, with the uniform standing in for the color of a player's skin. Or maybe the racism uncovered by Price and Wolfers is actually an extension of this more essential bias against certain colors.
If Price and Wolfers are right, then—all other things being equal—the Lakers may have a very slight advantage over the Celtics in the NBA Finals. But all other things are rarely equal. The boisterous crowds might amplify Boston's home-court advantage. Perhaps the Celtic green will soothe the referees, in the same way that green placebos work best for treating anxiety. There will be bad calls in this championship series, and there will be biased calls. It's just hard to tell which way they'll go. Wait, did I mention that Pau Gasol has brown hair?