Lecture Notes on Polygraphs and Lie Detection

Introduction

• Discussion on common dishonest behaviors (e.g., pulling sickies, fiddling expenses).
• Introduction of polygraphs as modern lie detectors.
• Use of polygraphs in various fields (e.g., courtrooms, police departments).
• 70,000 Americans take polygraphs annually for government jobs.

History of Lie Detection

• Lie detection dates back 2000 years (e.g., India using rice chewing).
• Modern polygraph invented in 1921 by John Larson, a Californian police officer.

Advances in Polygraph Technology

• Engineer Bruce White's contributions at Axiton Systems, Houston.
• Invention of the first fully computerized polygraph 25 years ago.
• Comparison of physics searching for truth in nature to polygraph searching for truth in human behavior.

How Polygraphs Work

• Key components: motherboard and computer algorithms for data processing.
• Physiological activities monitored:
  • Breathing rate
  • Sweat level (galvanic skin response)
  • Heart rate
• Setup process:
  • Expandable tubes for torso movement tracking.
  • Velcro plates on fingers to measure electrical activity related to sweat.
  • Blood pressure monitor attachment.

Polygraph Testing Procedure

• Standard procedure starts with simple questions to establish baseline physiological responses.
• Control questions are asked to see responses when lying is involved:
  • Example questions include mundane tasks to assess truthful responses.
• Subject's physical responses to emotional questions (e.g., personal relationships).

Significance of Physical Responses

• Physical signs of lying:
  • Increased sweating
  • Elevated pulse
  • Shortness of breath
• Skilled examiners can interpret these signs accurately.

Limitations of Polygraphs

• Not infallible; famous case: Gary Ridgway (Green River Killer) passed a polygraph despite committing crimes.

Tips for Beating Polygraphs

• Suggestions for subjects to manipulate responses:
  • Think of exciting/scary thoughts during control questions.
  • Use pain (e.g., biting tongue) to mimic physiological responses.

Innovations in Lie Detection

• New upgrades in technology:
  • Muscle contraction detection via a hidden pad.
  • Temperature monitoring on the face using cameras.
• Importance of staying updated with technological advancements in lie detection.

Conclusion

• Emphasis on the evolving nature of lie detection technology.
• Future implications for politicians and public figures as technology improves.