Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Jack Asher

Second Advisor

Dr. Brad Huitema

Third Advisor

Dr. Dale Brethower

Access Setting

Masters Thesis-Open Access


The purpose of this study was to determine the validity of the polygraph in a controlled laboratory setting. The Guilty Knowledge Test (GKT) was the procedure employed in conjunction with the galvanic skin subjects over the two trial each. Overall the polygrapher was correct 44 times, out of 80 trials. This number of detections exceeded chance (p<.001) levels. The manipulation of subject motivation with a monetary reward increased detection rates significantly (p<.05) in comparison to those offered money. With each subject being tested over two trials, there appears to be a habituation effect as indicated by a decrease in detection from trial one to trial two. The relationship fell slightly short of significance at the (p< .05) level. In general the level of the subject motivation may play a major role in the detection of subjects who attempt deceit.