A few years ago I reported on this story: In 2005, Michael Kosfeld, Markus Heinrichs, Paul Zak, Urs Fischbacher, and Ernst Fehr published a paper, “Oxytocin increases trust in humans.” According to Google, that paper has been cited 3389 times. In 2015, Gideon Nave, Colin Camerer, and Michael McCullough published a paper, “Does Oxytocin Increase …