How Does Truth Serum Testing Differ From Polygraph Testing?

Truth serum and polygraph testings are techniques of interrogation commonly used for lie detection. Both methods have become popular icons and are often seen in movies and television, particularly crime dramas.

Truth Serum Testing

• The common drugs used in a truth serum testing are amytal and sodium pentothal. These drugs create a state of relaxation in the central nervous system, allowing a person to speak freely. This allows more effective questioning by a skilled interrogator.

Polygraph Testing

• A polygraph is a machine that attaches sensors to a person. These sensors measure breath rate, pulse, blood pressure and perspiration. These measurements are intended to indicate stress responses during questioning. A person's signals are recorded on a graph and examined by a professional.

Reliability

• Both forms of lie detection have little evidence to prove their accuracy. Any statements made through these testings are inadmissible in court. Despite their lack of reliability, both methods continue to be used outside of judicial settings.