Something I learned in a journalism class relates to this: "I'm going to give what is probably a very contrarian view here: scientific studies show that Caucasian features allow for a higher standard deviation than Asian features."
Don't just claim "scientific studies say X;" cite studies Y, Z, and A. I'm not saying that your claim is wrong, but it sounds implausible to me, and I suspect that, if such studies exist, they probably indicate that whites find it easier to differentiate other whites and Asians find it easier to differentiate other Asians (I'd be curious: are such studies done solely in the United States? If so, they'd be worthless).
You're quite right, of course--but I think that, in any case where the person actually has access to a study they mention (and isn't, say, typing this reply on a phone while in gridlock on public transit), they would simply cite it, as it would strengthen their argument at no cost. Thus, you can take any assertion, including mine, that mentions that "studies say", as simply positing that there could be studies of such a type, and exploring the any implications made possible by that assumption.
In this particular case, I believe the best I can give you is that I heard it from a science podcast of some sort.
Don't just claim "scientific studies say X;" cite studies Y, Z, and A. I'm not saying that your claim is wrong, but it sounds implausible to me, and I suspect that, if such studies exist, they probably indicate that whites find it easier to differentiate other whites and Asians find it easier to differentiate other Asians (I'd be curious: are such studies done solely in the United States? If so, they'd be worthless).