I wrote a webpage in 2015 about the Decety paper, what it was and how it was presented in the media, which might be of interest. The paper seemed highly suspect in various ways even at the time. I added an update in 2017 that "new analysis shows that the original study failed to adequately control for the children’s nationality". On the (unfinished) page I'm using the paper as an excuse to teach myself basic statistics and research methods.
http://www.adamponting.com/decety/