Ever had a so-so stranger turn into a hottie—once you spent time together? Turns out, we’re more attracted to people we know, according to this study’s series of experiments.

In the first experiment, subjects rated the attractiveness of high school yearbook pics—either strangers or past classmates. The more familiar, respected and liked the people were, the more physically attractive the subjects rated the photos.

The next two experiments looked at whether the most valuable members of a task-oriented group seem hotter to the others in the group. The first group was a university rowing team, where talent, effort, liking and respect were all highly correlated with physical attractiveness. The second group was archeology students working on a 6-week dig. Again, familiarity, intelligence, liking and respect all influenced attractiveness.

Bottom line: Good bone structure can only take us so far and after that, our personalities do the heavy lifting.