Jonah Lehrer points to studies finding that qualities like generosity, move through social networks. He pulls this quote from James Fowler on what this means for free will:
Everyone always tells me that this research is so depressing and that it means we don't have free will. But I think they're forgetting to look at the flipside. Because of social networks, your actions aren't just having an impact on what you do, or on what your friends do, but on thousands of other people too. So if I go home and I make an effort to be in a good mood, I'm not just making my wife happy, or my children happy. I'm also making the friends of my children happy. My choices have a ripple effect.