[Esel Mann]

Sherwood, are you referring to the experiments from the OP's article or are you referring to other experiments from other similarly conducted studies?

Validation of a persons class did not appear to be addressed in any of the experiments of the OP's referring article. Normally I would not have given it another thought and would have presumed that they did proper validation of such, except for the the fact of their choice regarding the intersection experiment which lead me to wonder if they ensured validation of class at all.

Nevertheless, a thesis of this type is interesting and certainly will catch the eye of The Economist which I have found does a fairly good job at looking into such studies.