I was wondering the other day, when I told someone he was such a "white boy", what made me conclude this. Was it directly due to the fact that he was white and acting very stereotypical OR if I would be able to conclude this based solely on actions (all PC-ness aside). I started thinking harder and then I decided I should tease out if we see a figure of a person if we could really accurately tell what race someone is just by looking at them.
The way I'd figure it you could sculpt some bodies based on a selection of different racial/ ethnic backgrounds. The models would be an accurate representation of actual people in the nude. These sculptures should be cast in very oddly colored material (green or blue or something) as well as material that accurately represents the skin tone of the model.
Now the subjects are given a style of survey at random: check the box or written. They are showed each model in random order and they are to either check the box or fill in the supposed race of the model. Models are shown multiple times to the same subject cast in different colors to control for any sort of "color bias". Additionally, clothing should be chosen to represent each model. As a second part the models are shown to the subject with clothes that match or do not match the actual model.
In my opinion, if the subjects cannot accurately identify the models then a lot of what we perceive as race or ethnicity is not in physical appearance but in actions. Additionally, if there is a discrepancy in accuracy between nude and clothed models then we as people do put a lot of stock in the dressing of the individual.