“Control” questions tend to be broad and sweeping, spanning a long period of time. Common “control” questions include:

• Have you ever lied to a loved one?
• Have you ever taken something that does not belong to you?”
• Since the age of 18, have you ever considered hitting someone in anger?

Since most everyone can answer “yes” to all of these questions, the typical examinee will admit to one or two minor transgressions.The polygrapher will then move to contain these admissions, in order to leave you with the uneasy feeling that you haven’t told all. The polygrapher accomplishes this by trying to convince you that any further admissions on these questions will call your character and integrity into question, and that you would end up failing the “test” before it even begins.

Following limited admissions, the “control” questions often end up structured as, “Other than what you told me, have you ever lied to a loved one?” The theory is that when you answer the question “no,” you must still be withholding something, or at least feel uneasy about not remembering some incident from long ago. The polygrapher treats your response to this question as though it were a lie.

So the machine detects transgressions, not lies, correct? 

That's not what I meant.  Sorry.   

Why would CM's have any effect on a control question and not effect the relative question?  Isn't it the relative question that could pose a problem to the exam taker?