Apparently doing something good can be contagious. Or at least this seems to be the case with solar power adoption. According to a study by Yale and New York University published though Marketing Science, individuals are most likely to install solar panels on their home if one of their neighbors has also done so. The study, “Peer Effects in Diffusion of Photovoltaic Panels”, took a close look at solar installation clusters between January 2001 and December 2011 throughout the state of California. They found that a resident was most likely to install solar panels if solar panels had already been installed within that resident’s same zip code.