The study is not published in Psychology Today (btw--Psychology Today has completely lost its credibility, IMO, by allowing all sort of crapola to be printed under its banner by unqualified bloggers). It's in Personnel Psychology, some sort of academic journal about, well, personnel pesychology. It has a pretty low impact rating and seems to be fairly obscure. I have no idea why this got picked up by NPR, truly. I follow social science press pretty closely and it continues to mystify me why some of these stories get hot. This is an example, because it's hard to make sense of and perhaps not all that exciting in the first place.
Apparently the goal of the article is to challenge these beliefs in these particular sub-disciplines. I guess. I find it strange, too, but it seems to be speaking to a very specific audience and wasn't really intended to be picked up more generally, imo. I am not familiar with these specific areas, though, so can't speak to how important this assumption (that performance is normally distributed)is for them.
I went back and looked at it again, and I think you have it right.
