The Relative Utility of Skin Resistance and Skin Conductance.
Final rept. Sep 89-Jan 90
DEPARTMENT OF DEFENSE POLYGRAPH INST FORT MCCLELLAN AL
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The effectiveness of two circuits constant current skin resistance constant voltage skin conductance used for measuring electrodermal activity during a psychophysiological detection of deception PDD examination were researched in an analog study conducted by the Department of Defense Polygraph Institute DoDPI. Thirteen DoDPI instructors tested a group of 65 subjects who had been assigned to one of four conditions 1 innocent, 2 guilty of one mock crime, 3 guilty of two mock crimes, or 4 guilty of three mock crimes. Half the subjects were tested with a multiple issue test format which contained questions about all three crimes under investigation. The remaining subjects were tested using a series of three single issue examinations, each containing questions about only one crime. Following the examinations, two objective measurements were made on the skin conductance response and skin resistance response waveforms. One measurement assessed the number of centering adjustments made during the examination, and the other measurement compared the electrodermal responses to the nearest millimeter for both the relevant and the control questions. The constant voltage circuit skin conductance required approximately half the number of centering adjustments as the constant current circuit currently in use throughout the polygraph field. Because the two circuits do not have the same scale, sensitivity settings could not be compared. However, when the actual size of the electrodermal responses were compared the differences were not statistically significant suggesting that numerical scores and resultant decisions based upon those responses would have bee the same.
- Medicine and Medical Research
- Stress Physiology
- Miscellaneous Detection and Detectors