Nicolas Gueguen, a psychologist at the University of South Brittany, and his colleague Celine Jacob found not only that male patrons gave higher tips than female patrons in general, but that men gave between 14.6 percent and 26.1 percent more to waitresses wearing red, while color had no effect on female patrons' tipping behavior at all.
Gueguen and Jacob instructed 11 waitresses in five restaurants to wear the same T-shirt in different colors -- black, white, red, blue, green, and yellow -- on different days over a six-week period.
They were told to act as they normally would to all customers and to record how much they received as a tip from each customer.
Writing in the journal Journal of Hospitality and Tourism Research, the researchers cited previous research that found red increases the physical and sexual attractiveness of women.
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