From NPR:

A new study finds many waiters and waitresses feel that black Americans generally tip less than restaurant diners who are white. The study, by a researcher at Cornell University's School of Hotel Administration, found that blacks tip on average 20 percent less than whites. In addition, restaurant workers of all races dislike waiting on black people because they assume the tips will be less no matter how good the service.

Now what would have been interesting in the study is a follow-up question asking why. There were responses to this piece on NPR this morning, and some people wrote in to basically say, "Why should I tip someone who's just doing their job?"

The NPR piece strongly implies that simple ignorance of tipping customs in America is to blame:

He says cultural elements -- blacks have avoided sit-down restaurants in favor of take out or self-service eateries -- institutionalized racism that exists in the restaurant industry and education about tipping are all behind the discrepancy. "How do people learn about tipping? If you don't go, you don't know."

Which I happen to think is idiotic. Again, the study doesn't delve into the question, but I find it absurdly difficult to believe that most people don't know socially-accepted tipping standards.

Many places automatically apply a gratuity for larger parties. Between all the media (TV, movies, etc.) people have to have picked up this knowledge. And even if they didn't, if we're so culturally racially segregated that blacks and whites don't ever go to a sit-down restaurant together (and subsequently discuss how much tip to leave)...well, I just don't buy it.

I remember an incident when I was in a McDonald's a couple of years ago, and a black woman and her teenage son were leaving. The woman was in the process of cleaning her tray off into the trash, and the young man said, "Why you want to be like a white person?"

And I thought, "And how is that?" Though I didn't say anything.

I would be interested to see, then, how blacks and whites responded to surveys asking them how much restaurants expected them to tip, how much they actually tipped, and why.