According to [Erin Whitchurch, Timothy Wilson, and Daniel Gilbert's] paper, published in Psychological Science and based on an experiment conducted with undergraduates, women find men who may like them more appealing than men who definitely do.
A group of female students at the University of Virginia were told they were evaluating whether Facebook could work as an online dating site; 47 women learned that male students from the University of Michigan and U.C.L.A. had viewed their profiles as well as those of 15 to 20 others. The women were then shown Facebook profiles of four “likeable, attractive” men. (The profiles were fake.)
One group of women was told that these four men were those who liked them the most, a second group heard that these men rated them as average and a third group was left in the unsettling position of thinking that the men might like them either the most or an average amount.
Not surprisingly, women were more attracted to men who found them attractive than men who rated them average. This is called the “reciprocity principle,” which holds that a woman should like a man less if he doesn’t like her much, and reflects earlier research. The shocker was that the women who found the men most attractive of all were those who weren’t sure just how much the men liked them.
--Pamela Paul, NYT, on evidence for the Tao of Steve