The Real Poop
Let us tell you the truth, the whole truth, and nothin' but the truth.
...and some jokes. Come on, you know where you are.
The life of a polygraph examiner (also called a forensic psycho-physiologist) is a challenging one. It's full of intrigue, astute observation, and...well, a whiff of perspiration.
You're basically tasked with finding out if someone is lying—hence why the polygraph is called the lie detector test. You find out if someone's lying by measuring the body's responses to pointed questions like "Do you like the color purple?" and "Did you take the last cookie in the cookie jar?" and finally "Did you throw your wife off a cliff so you could collect the insurance money?"
In addition to being trained to decipher body language and the little tells people give when they're trying to pull a fast one, a polygraph examiner asks a series of control questions and then more controversial ones—all while the person being examined is hooked up to a machine that measures everything from heart rate to breathing to amount of sweat (source).
So, yes, being able to dig up a person's innermost secrets sounds delightful, but how much will you be paid for it? You'll likely take in about $30,000 your first year, building up to a typical wage of $75,000 a year (source). Not too bad, huh?
It's also a life of controversy. Polygraph results are not admissible in all states. Certain states, like California, Florida, Nevada, Georgia, and Arizona, allow their results as evidence in courts if both the prosecution and defense agree to allow them. Other states like New York and Texas do not allow polygraph results to be entered no matter who says it's okay (source).
So make sure you're in the right state. So long as you are, you could get hired by the cops, the courts, the FBI, or even the CIA (source).
There's also work in big corporations who want to catch spies, embezzlers, thieves, and pretty much anyone who would "do them wrong."
Each polygraph test takes between three and four hours to complete, and by law, you can't do more than three in a day (source). (Nor would you want to—it's pretty darn tiring trying to get into the mind of your subject.) At $400 to $600 each exam, you most likely make a little over $1000 a day, however you may not find work every single day.
To get into this line of work, you'll have to go to a polygraph school like the American Polygraph Academy or other APA accredited schools. You'll complete a certain number of polygraphs in order to graduate and then you'll get your certificate.
If you want to work for the CIA or other high-profile government organizations, you'll need a BA in criminology, forensic psychology, or criminal justice.
Keep in mind, your job is to discover the truth, not just weed out the liars. In many cases, people want to take lie detector tests to prove their innocence. But you might also collect evidence to prove people guilty, so you'll have to be comfortable and professional while questioning and talking to all different kinds of people. In order to pull this off, you should be highly detail-oriented (number one job qualification of all time), observant, and even-tempered.
That means, you can't go bursting into a tirade of "Liar, liar pants on fire!" in the middle of conducting a test. You also can't let on that you think someone's guilty, for fear of giving them a false positive or skewing the results.
You'll be held to a high moral standard. You'll probably need to get a security clearance and background check before you can start working in the field as well, so keep your nose clean and stay outta trouble.
And before you ask, no, soaping up your nose will not make up for the time you robbed Taco Bell.