I recently came across an exceptionally awesome story based on this mildly bizarre idea, namely this one by Teneskel: http://www.literotica.com/s/culture-shock-1. If you're not sold on the concept, I encourage you to read that story. Frankly, after I did, I began to find ordinary Earth humans a little lacking - to the point that I would have expected many other authors to pursue this fantasy. Yet I don't really even know where to look for it. I'm aware of a couple other stories that have this element, but as part of a larger (and even weirder) scheme: see for example http://www.tpe.com/~altarboy/nt050900.htm and http://f3.to/demon-man/?q=node/352. But I am not aware of any good exposition of the subject other than the excellent and very short one referenced above. So, I thought I'd mention this, partly in the hope that someone might direct me to further material, and partly just to advertise an awfully under-represented idea.