The amount and type of laughter between two people can potentially tell us much more than that they are sharing a joke. For example, friends laugh more than strangers, and shared laughter can be an indicator of sexual interest between a couple. But as onlookers, how well can we use the sound of laughter to make these kinds of inferences? A new study in PNAS is the first to investigate this and it turns out, regardless of our culture or where we live, we are pretty good at using laughter to identify the nature of other people’s relationships. In other words we laugh differently with friends than we do with strangers, and the neutral listeners can tell the difference. http://digest.bps.org.uk/2016/06/you-laugh-differently-with-friends-than.html Study: http://www.pnas.org/content/113/17/4682