Polygraph testing, also known as a lie-detector test, is typically used for employment screening for government careers. They can also be used for employee theft testing, special events, infidelity, wrongly accused claims, criminal testing, personal testing, and numerous other reasons.

For those who have or will take one, polygraph testing can be extremely stressful and nerve-racking. The major reason for this is because most people don’t understand how a polygraph works.

The polygraph or “lie detector” measures and records physiological responses like breathing rate, pulse, blood pressure, and perspiration. The underlying theory is that when people lie they get measurably nervous about lying. These physiological changes help determine that they are in fact lying.

The most intimidating part of the polygraph is being hooked up to the sensors that collect physiological data.  Once you’re attached to the sensors, the exam will likely start with a pre-test interview.  This gains information that will be used for control questions. The examiner may ask you to deliberately lie to test your responses. This helps determine the similarities of your physiological responses to the actual test. They will then administer the actual exam.

Make sure you are well-dressed, well-fed, and well-rested before a polygraph exam. Answer all questions truthfully to the best of your ability— it is better to respond with a truthful answer that the examiner might not want to hear, than to lie.