Author and intelligence scholar Ernest Volkman claimed that the CIA’s sole means to check the bona fides of its Cuban assets during the Cold War was the polygraph. Regardless of whether it was the Agency’s only means, the CIA clearly relied too heavily on polygraph examinations. To exploit this vulnerability, Russia’s foreign intelligence service, the KGB, provided Havana with instructions on counter-polygraph techniques. The resulting solution was quite simple. Both services knew that pathological liars can pass polygraph exams because they believe so strongly in their lies that the machine cannot detect any physiological response indicative of deception. As such, both nations trained their agents to mimic the success of a pathological liar by accepting their lies as the truth.
As a result, dozens of Cuban double agents passed their CIA polygraph exams. Those who failed tended to be protected by their Case Officer (i.e., spy handler), who made excuses for their agent’s difficulties. Cuba also exploited another CIA vulnerability – bean-counting. Havana knew the CIA measured its personnel by their productivity rather than by their actual success. Castro’s spy services were also benefited from the CIA’s arrogance in handling agents from Third World nations, as well as its cavalier disregard for the Cuban Intelligence services.
Cuba’s counter-poly techniques were also taught to its other spies, including Ana Belen Montes, a high ranking penetration of the Defense Intelligence Agency. Montes passed one polygraph exam during her DIA service. A second examination, randomly scheduled while she was under investigation, was discreetly canceled by DIA Counterintelligence. Investigators were rightfully concerned she would again pass the exam, crippling the case being built against her.
Cuba Confidential 
Pingback: Cuban spies trained by KGB to defy polygraph tests | Babalú Blog