Emma was probably referring to some studies that have happened in the past couple of years that actually do lend some evidence to that claim.
Basically, there was one study where people were shown different people’s skin getting pricked, and people tended to have a stronger negative reaction when seeing their own skin color getting pricked. And there was another study where people were shown a picture of someone, and then asked to rank how much pain they thought that person would feel in a given situation (like stubbing a toe, getting an injection, etc.), which found that people tended to think black people felt less pain than white people.
Here’s one article that references both studies:
George Zimmerman followed Trayvon Martin because he perceived him as dangerous. The defense argues he was, the…www.slate.com
So it probably would have been good if Emma had offered a little more background or a citation, rather than assuming everyone reading the article would know what she was talking about, but an any rate, that claim actually does have some basis.