Nonombre,
It would seem to me that your concerns about breathing control would quickly produce an untenable situation.
The subject comes in to the exam and is nervous, even though he has nothing to hide and intends to be truthful. In order to control his anxiety and remain calm, he consciously controls his breathing.
The examiner asks him why he is controlling his breathing. The answer he receives is, “To remain calm.” Apparently, the examiner would then advise the subject that he is not permitted to consciously control his breathing, and that continuing to do so will constitute Purposeful Non-Cooperation, and he will fail.
If the subject is consciously controlling his breathing, he is almost certainly doing it for one of two reasons. He could be nervous in general despite having no plans to lie, and so he controls his breathing simply to remain calm and not let his anxiety become a problem. Or, he could be planning to withhold information or lie about one or more things and is controlling his breathing because he thinks that will help him get away with it.
The problem I see with this is that in the first instance the examinee is doing absolutely nothing wrong. He is not attempting to lie or withhold any information. He is attempting to cooperate with the testing procedure. In fact, he is exhibiting a measure of control that is to be admired and encouraged in any law enforcement professional. Yet, in order to avoid skewing the data for the “test” he will be prohibited from exhibiting such control.
I think what makes the situation untenable is that it is unfair to tell a subject that they cannot attempt to remain calm. They are essentially being told to let themselves panic, if appropriate, and that to do anything to control their reactions will result in them summarily failing the test. It seems difficult to defend instructions to the subject that they engage in no measures to avoid anxiety or panic. Instructions to tell the truth are entirely appropriate, but I understand it is exceedingly difficult to determine if those instructions are being followed or not.
Since the polygraph cannot detect deception and the corresponding violation of the instructions to tell the truth, it is instead used to detect violations of the instruction to breathe normally. In that capacity (as an instrument to measure respiration rate) I’m certain the polygraph performs admirably.
I can easily envision a scenario wherein the subject is told, after a series of questions during which the examiner noticed controlled breathing, to immediately stop controlling his breathing and to just breath “normally.”
Subject: “But I wasn’t lying! Can’t you tell? I’ve just told the truth on every single question – why are you asking me about my breathing?”
Examiner: “Well, I can’t tell if you were lying and controlling your breathing to conceal that fact, or if you were being truthful and controlling your breathing to avoid becoming overly anxious.”
Subject: “But isn’t this supposed to be a lie detector test? Can’t you tell I wasn’t lying! I was telling the complete truth!”
Examiner: “Okay. You just failed for purposefully not cooperating with the instructions.”
The subject would then be reported as having failed, even though he told the complete truth and didn't withhold any information. All he did was not allow himself to hyperventilate during an interrogation. I just don't see how that can possibly be considered fair.
I also don't see how it can be corrected unless the polygraph is no longer used in such a capacity. And I'm fine with that.