Is the Dog Responding When I'm Crying?

Dogs sense a great deal about our inner lives by observing our behaviour, and also by sniffing out our excretions or sweat. So i wonder, in an experiment like that, if the humans are faking it, wouldn't the dogs kind of know they're faking it? I think that's a really good complaint about the experiment. And those experimenters, i think, realized it after the fact, that, oh, well, maybe the dog wasn't responding because the person didn't smell like they were stressed,. so why should the dog respond? Another part of it is, even if they're really sensitive to or physiological or behavioral changes, which i think they are...