How do mean? I thought it didn't matter who you were, that the test is generic?
That a polygraph is generic? No, but I don't know if that is the right word to use though. As in the case of Alan and Bob (post #2), a polygraph is useful only so far as accuracy is concerned. The machine could pick up internal biases that have nothing to do with the issue the person is being questioned about, rather the capacity of the person. The fact of being human and having the ability to be hooked up the machine is immaterial compared to the mental capacity to answer those questions correctly.
Case in point. Take the "generic" Jerry Springer guest (assuming they are as mentally hilarious as they are portrayed). Supposing the generic guest has some serious social problems, mental issues, whatever, and you hook that person up to a polygraph machine, you would definitely not have a reliable result. They are not applicable to the standards of the test. This is where the comment on "polygraph machines require a certain degree of discipline" comes in. There are a few reasons for this assumption.
One assumption is that (in my mind) to have a reliable polygraph readout presupposes a "rational person." This is an issue that is highly debate within the context of the law. As in the case of pleas of insanity, a person who murders another (assuming the existing precedence) and is mentally challenged is not judged under the same rubric as a "rational person." In a sense, the mentally challenged person may not in some way understand that what they did was wrong. Theory and precedence determines that because they do not know that what they did was wrong, they cannot be held to the same standard as a rational person.
So with that being said, do all persons hooked up to a polygraph infer some manner of generic quality? I would say yes
in so far as the physical component is concerned, that they have ears to hear the question, a mouth to provide the response, and vitals to monitor in order to gauge the responses. Of course responses could come via different ways, but that is just to deliver the point of responses etc. But on the whole, I would say no