NCJ Number
51122
Journal
Psychophysiology Volume: 12 Issue: 3 Dated: (MAY 1975) Pages: 321-330
Date Published
1975
Length
10 pages
Annotation
THE EFFECTIVENESS OF FIELD POLYGRAPH EXAMINATIONS IN DETECTING TRUTH AND DECEPTION IN A MOCK CRIME SETTING AND FACTORS THAT MAY CONTRIBUTE TO SUBJECT BELIEFS ABOUT THE ACCURACY OF POLYGRAPHS WERE INVESTIGATED.
Abstract
SEVENTY-TWO VOLUNTEERS FROM INTRODUCTORY PSYCHOLOGY COURSES AT THE UNIVERSITY OF UTAH RECEIVED EXTRA COURSE CREDIT FOR SERVING AS SUBJECTS. THEY WERE ASSIGNED TO EXPERIMENTAL CONDITIONS ACCORDING TO A PREDETERMINED RANDOM SCHEDULE. THIRTY-SIX SUBJECTS WERE GUILTY OF TAKING $10, AND THIRTY-SIX SUBJECTS WERE INNOCENT. A FIELD-TYPE INTERVIEW WAS FOLLOWED BY A ZONE COMPARISON CONTROL-QUESTION POLYGRAPH EXAMINATION. A KEELER FIELD POLYGRAPH WAS USED TO RECORD PHYSIOLOGICAL ACTIVITY AND FIELD (SEMIOBJECTIVE) AND QUANTITATIVE EVALUATIONS OF CHARTS WERE MADE. PERSONS WHO EVALUATED THE CHARTS WERE NOT INFORMED ABOUT THE GUILT OR INNOCENCE OF EACH SUBJECT. DURING THE ACTUAL POLYGRAPH TEST, 10 QUESTIONS WERE ASKED OF SUBJECTS ON THREE TRIALS. USING THE BACKSTER TECHNIQUE, BASED ON THE THEORY THAT DECEPTIVE PERSONS WILL SHOW LARGER RESPONSES TO RELEVANT AS COMPARED TO CONTROL QUESTIONS AND TRUTHFUL PERSONS WILL HAVE LARGER RESPONSES TO CONTROL AS COMPARED TO RELEVANT QUESTIONS, SCORES WERE OBTAINED FOR EACH OF THE FOLLOWING CONTROL AND RELEVANT QUESTIONS: RESPIRATION AMPLITUDE AT TWO DIFFERENT POINTS IN TIME, RESPIRATION CYCLE TIME, SKIN RESISTANCE RESPONSE, PULSE AMPLITUDE, AND BLOOD VOLUME. THE POLYGRAPH TECHNIQUE DISCRIMINATED BETWEEN GUILTY AND INNOCENT SUBJECTS AT LEVELS WELL BEYOND CHANCE. EXCLUDING INCONCLUSIVES, THERE WERE 81 PERCENT CORRECT DECISIONS. SKIN RESISTANCE WAS BETTER THAN CARDIOVASCULAR AND RESPIRATION MEASURES IN DISCRIMINATING BETWEEN GUILTY AND INNOCENT SUBJECTS. BLIND EVALUATIONS OF CHARTS BY FIVE ADDITIONAL EXAMINERS PRODUCED HIGH AGREEMENT AMONG EXAMINER DECISIONS AND A MEAN CORRELATION OF 0.86 AMONG TOTAL SCORES. IN SPITE OF EFFORTS IN THE STUDY TO MAKE POLYGRAPH EXAMINATIONS IN THE EXPERIMENTAL SETTING AS REALISTIC AS PRACTICAL, CAUTION IS RECOMMENDED WHEN ATTEMPTING TO GENERALIZE ALL OF THE RESULTS TO FIELD SITUATIONS. MORE RESEARCH IS NEEDED TO EXPLORE DIFFERENCES IN SUBJECT POPULATIONS AND SITUATIONAL DETERMINANTS DISTINGUISHING THE FIELD SITUATION FROM THE LABORATORY SETTING. SUPPORTING DATA AND REFERENCES ARE INCLUDED. (DEP)