Skin conductivity (i.e., resistance across surface of the skin) varies with many things: fear, anxiety, excitement as well as deception. This rudimentary device is an approximation of the more sophisticated Galvanic Skin Response (GSR) Meter.
A polygraph works by testing heartrate (via blood pressure), breathing rate, and GSR - the responses to various questions (standard ones: "Is today Friday?") is compared to the responses to relevant questions ("Did you kill Mother Mary?") and so on. It's notoriously inaccurate as a device for measuring "deception" - all spies are trained how to defeat it (to wit, it's never caught a spy - Aldrich Ames, the most notorious CIA mole passed two of them), but it is of some utility in exacting confessions from those ignorant of its limitations.
Reader Comments (Page 1 of 1)
james @ Mar 24th 2006 11:13AM
Skin conductivity (i.e., resistance across surface of the skin) varies with many things: fear, anxiety, excitement as well as deception. This rudimentary device is an approximation of the more sophisticated Galvanic Skin Response (GSR) Meter.
A polygraph works by testing heartrate (via blood pressure), breathing rate, and GSR - the responses to various questions (standard ones: "Is today Friday?") is compared to the responses to relevant questions ("Did you kill Mother Mary?") and so on. It's notoriously inaccurate as a device for measuring "deception" - all spies are trained how to defeat it (to wit, it's never caught a spy - Aldrich Ames, the most notorious CIA mole passed two of them), but it is of some utility in exacting confessions from those ignorant of its limitations.