Missnina,

It is not at all unusual for CIA applicants to be subjected to as many as three pre-employment polygraph sessions. It seems that virtually everyone is initially accused of "having problems," badgered for admissions, and then scheduled for one or more follow-up seances. That said, the CIA does have a very high pre-employment polygraph failure rate...

At this point, when asked what you know about polygraphy, you might want to choose the "complete honesty" approach and mention that you have researched it on-line. The Agency's polygraphers might well expect that by the time an applicant comes in for his or her third polygraph, he/she will have done some research, and might have a hard time believing someone who claims not to have done so.