The miscommunication here is I was on the same page as OP because I've seen the study he was alluding to (and actually got one of the points wrong). I incorrectly assumed that it was common knowledge. It's referenced here, and yes I am aware that this article is attempting to "debunk" it, but I think the counterpoints it makes are quite weak: https://www.vox.com/2015/7/24/9027195/haskins-sawhill-norms-...