"So it's more than just those who are susceptible to believe the polygraph, it does have some success. Efforts to beat the polygraph are largely ineffective and usually very detectable."
It has nothing to do with "beating" a polygraph. A polygraph isn't something you beat or don't beat. A polygraph in no way shape or form tests whether or not you are telling the truth and under normal circumstances it's results have zero relationship to whether or not you are telling the truth. It's just some random coincidental biometric data. You may as well be measuring the wind speed while asking me the questions or flipping a coin, either will have just as much connection to the veracity of the answers I'm giving which is to say absolutely zero.
"But I seriously doubt *you* could beat it unless you are a pathological liar who just doesn't care anything about truth, ethics or morals."
Whether or not I beat a polygraph has nothing to do with personal ability, pathological lying, or anything else but random chance the same as anyone else since the test results have absolutely nothing to do with whether or not I'm telling the truth. Which is why, nobody should ever agree to take a polygraph unless you are guilty as hell, you know you were sloppy and there is evidence to find, and you are taking the 50/50 chance the random result will be a pass and they might not investigate deep enough to find said evidence. Otherwise, especially if you are innocent, you should never ever take a polygraph.
Actually, if anything, trying to "beat" a polygraph and treating like a real test is likely the only way to create a correlation between the results and whether or not you were telling the truth.
Do not confuse the fun and entertaining television show mythbusters with actual controlled science. They are conducting informal experiments for fun using sciencelike methods not engaging in actual science. Mythbusters also determined that CD's exploding in 56x CD-ROMs was a myth using a high rpm dremel tool. The problem is I personally replaced dozens of Acer 56x CD-ROMs when CD's had exploded in them rendering the drives useless. Mythbusters did not test all the conditions or all the possibilities and therefore came to an invalid result. Mythbusters is fun but I am able to point out flaws in their methodology on almost every episode. Also, mythbusters and other television shows intentionally spread misinformation to aid police efforts. This is the source of their bunk results on LIDAR, the old myth about needing to stay on the line to trace a phone call, even the new myth that it used to take 5 min but now they can trace you immediately if you are on the line. All of that is ridiculous, you make a call, a record is recorded of you making the call, the police have a hotline to a department in the phone company that exists just for looking up the records and the phone company works on the honor system for legal authority to do the lookup. Or at least they did in the 70's. Now they can probably just access the information directly with a computer. The police don't need you to stay on the line or even to be on the line, they can see where you made the call from in 30 sec, 5 min, or three months. There are no shortage of intentionally implanted subliminal messages and bunk truths on TV planted for the aid of law enforcement and if you ever plan a robbery based on what you've learned from TV you are screwed. The entire concept of needing to beat a polygraph, the tense moment, the need to be a psychopath/sociopath to defeat one. All TV myths spread to aid law enforcement.
"Polygraphs may not be a perfect tool, they *can* be manipulated by sufficiently trained people"
Polygraphs can be beaten simply by being aware they are nonsense. The sophisticated techniques for beating them really come down to nothing more or less than telling people the format and what to expect. There is a pdf linked TFS and a book mentioned in a comment already. Read either and upon finishing the reading you are done... done learning information designed to counteract the brainwashing into believing a polygraph that has happened in your life.
Wake up buddy. Polygraphs aren't real. And the probability that all the evidence the police found of someone's guilt really being as convincing as it sounds is on par with how compelling and convincing the signs of God's work are to a believer. When you look at reality through a focused lens of assumption suddenly everything looks like it is related to what you are looking for and suddenly total coincidences that occur for all of us every day look like "one hell of a coincidence."