Very late comment, but I find this truly amazing. Yes, some cats are too dumb to fully grasp what's happening, but they do give the human a look of concern. Their reactions could be manipulated, but I find interesting how dogs look forth and back, while most cats remain fixated in the real human. Not very rigorous, but very cool anyway.

I've always thought a good mirror test shouldn't be just a mark, but something that looks like a venomous insect, to stimulate the subject to look for it.