Module 5 - Polygraph Testing & Forensic Document Analysis

A typical polygraph examination room. Click the image to enlarge.
Photo courtesy of Sergeant A. Kowalyk, 2005.

When a person is being deceptive and telling a lie - no matter age or gender - certain universal physiological stress responses are triggered in the body.  This fact led to the development of a forensic instrument that detects and monitors these physiological responses. The instrument developed is called the polygraph, but it has commonly become known as the lie detector.

Forensic document analysis involves the examination of documents for which the source or authenticity is in doubt. The most common types of documents that are analyzed by forensic experts include letters, cheques, drivers licenses, contracts, wills, passports, and lottery tickets.  Verifying a questionable document may involve a visual examination (human-eye and/or microscope) and/or chemical analysis (chromatography).

• Lesson 1 of this module examines some of the structures of the nervous system that control the stress responses that occur when a person is being deceptive.  You will be introduced to the history and basic mechanics of the polygraph instrument. 
• Lesson 2 discusses the details of an actual polygraph test and how these tests are used in criminal matters. 
• Lesson 3 focuses upon the details of forensic document analysis and how this technique is used in policing. 
• Lesson 4 examines the details of two historical crime cases and one fictional crime case involving polygraph testing and forensic writing analysis.