Perspectives: Fickle Friends; May / June 2011; Scientific American Mind; by Kirsten Weir; 2 Page(s)

Have you ever had a friend who makes plans to hang out but cancels when a better offer comes along? Or a buddy who helped you through a bad breakup, then flirted with your ex? To scientists, these problematic pals are known as ambivalent friends. To a more slang-savvy crowd, they are called “frenemies.”

Either term has come to describe a range of complicated relationships—those that boost you up and bring you down, for any of a variety of reasons. They include the well-meaning friend who is overly competitive, the pal who is a pillar of support when times are tough but cannot quite take pleasure in your successes, and the college buddy who drops everything to lend you a hand when you need one but gossips about you later.