Though men don’t realize it, the color red on a woman is a powerful aphrodisiac, according to a study at the University of Rochester. Researchers Andrew J. Elliot and Daniela Niesta showed study participants a black-and-white image of a woman against a background colored red, white, gray, or green, and color pictures of the woman in a red or blue blouse. Men consistently perceived the woman wearing or highlighted by red as sexier, and they were 56 percent more likely to want to ask out the woman dressed in red, compared with blue. Color did not affect opinions of nonerotic traits, such as how nice the woman seemed. The psychologists believe the red effect (which almost none of the men indicated they were consciously aware of) has biological roots, since nonhuman male primates are particularly attracted to females displaying red when they are ovulating. Only men, not women, found women against a red backdrop to be better-looking, the study found.