Women buy sexier clothes when they're ovulating, researchers from the University of Minnesota found in a study they say could impact how products associated with looks are marketed.
"The desire for women at peak fertility to unconsciously choose products that enhance appearance is driven by a desire to outdo attractive rival women," said Kristina Durante, a post-doctoral fellow at the University of Minnesota's Carlson School of Management and lead author of the study.
"If you look more desirable than your competition, you are more likely to stand out."
The researchers found that ovulating women chose sexier clothing and accessories for themselves after being shown photographs of attractive local women than when they were shown photos of unattractive women from their area or women who live more than 1,000 miles away.
Women who were not ovulating did not make the same choice, and the ovulating women made it unconsciously, the researchers found.
The aim of preening during ovulation is to attract the best romantic partner, said Durante.
To do that, "a woman needs to assess the attractiveness of other women in her local environment to determine how eye-catching she needs to be to snare a good man," Durante said.
To a woman in New York chasing a mate in Manhattan or Brooklyn, a rival in Los Angeles poses little threat, she said.
Marketers should pay close attention to the findings of the study, which showed that ovulation has a "profound influence" on a woman's consumer behaviour, the researchers said.