The Truth About Polygraphs: The Science and Limitations of Lie Detectors

Polygraphs, first used in 1924, are based on the theory that lying triggers physiological responses like increased heart rate and perspiration. Devices measure these responses during questioning. The Control Question Test compares responses to control and relevant questions. However, polygraphs lack scientific evidence for unique lying patterns and are only about 75% accurate. True guilt is best proven by admission or evidence.

What physiological responses does a polygraph measure to detect deception?

• Heart rate, breathing, blood pressure, and perspiration

• Brain waves and muscle tension

• Body temperature and pupil dilation

• Eye movement and voice pitch

What is the primary purpose of control questions in the Control Question Test?

• To confuse the interviewee

• To establish a baseline for truthfulness

• To distract from the relevant questions

• To make the interviewee nervous

How does the Control Question Test determine if someone is lying?

• By observing body language

• By analyzing the speed of responses

• By comparing responses to control and relevant questions

• By checking for inconsistencies in the story

What is the accuracy rate of polygraphs according to studies?

• 50%

• 60%

• 75%

• 90%

What is considered the only reliable method to prove someone's guilt?

• Polygraph test results

• Witness testimony

• Person's own admission or clear evidence

• Behavioral analysis