A new study says that coffeehouses discriminate against women. Slate’s Tim Harford writes:

I’m a real cappuccino lover myself, but many of my female colleagues don’t seem to go for the stuff. I’d never thought too much about it until recently. I suppose I carelessly assumed that men and women have different tastes, probably as a result of different social influences. Now I know better: My female colleagues don’t go to coffee shops because they’re shabbily treated when they get there.

That’s the conclusion of American economist Caitlin Knowles Myers. She, with her students as research assistants, staked out eight coffee shops (PDF) in the Boston area and watched how long it took men and women to be served. Her conclusion: Men get their coffee 20 seconds earlier than do women. (There is also evidence that blacks wait longer than whites, the young wait longer than the old, and the ugly wait longer than the beautiful. But these effects are statistically not as persuasive.)

The study goes on to show that it’s not because of frou-frou drinks and, perhaps most significantly, the lag evaporates when the coffee is served by a female barista.

That last part is the most puzzling. In most cases where sexual discrimination is apparent, it’s not usually just the men that do it. Women fall prey to the same assumptions, sometimes to a lesser extent but sometimes even moreso.

Alan Jacobs has a theory:

Men, on the other hand, are more likely to give off every possible signal that they’re in a hurry. They stand closer to the people in line in front of them, they have their payment ready before it’s asked for, they plant themselves as near as possible to the barista and in some cases stare down the poor coffee-craftsperson until their drinks are ready, at which point they snatch up the cups and bolt from the store.

It seems to me that baristas, then, might be responding to these signals by hustling to serve the obviously impatient men, and relaxing a bit when they’re making drinks for women. And it also seems likely that male baristas would be more sensitive to the signals given off by their fellow men, more eager to show them that they share their emphasis on speed.

This is an excellent explanation! I wouldn’t be surprised if, when I was a service worker, that I acted with more diligence with men than with women. Not only are men more likely to be in a hurry, but they’re also more likely to get irate if they wait too long and likely to be more unpleasant if they get irate… but that doesn’t explain why the difference evaporates when women are the servers.