Using data collected from Facebook, Kevin Lewis (Ph.D. 2012) and colleagues examined one of the great unsolved puzzles of social science — do we form friendships with people because we share interests, or do we share interests with people because they are our friends? Study of Facebook patterns suggests interests in music, movies unlikely to spread among friends, Harvard Gazette, January 18, 2012. See also "Mysteries of Mate Choice" (Harvard Magazine, May-June 2012) which discusses research conducted by Lewis using data from on-line dating to explore how we choose romantic partners.