New measures improve the accuracy of the directed-lie test when detecting deception using a mock crime.
The present study tested the accuracy of probable-lie and directed-lie polygraph tests. One hundred and twenty men and women were recruited from the general community and paid $30 to participate in a mock crime experiment. Equal numbers of males and females were assigned to either the guilty or innocent condition with equal numbers in each group receiving either a probable-lie or a directed-lie polygraph test resulting in a 2 x 2 design with two experimental factors (test type and deceptive condition). Half of the participants were guilty and half were innocent of committing a mock theft of $20 from a purse. All participants were paid a $50 bonus if they could convince the polygraph examiner that they were innocent. There were no significant differences in decision accuracy between probable-lie and directed-lie tests, but respiration measures were more diagnostic for the probable-lie test. New physiological measures, skin potential excursion and a new respiratory measure improved the accuracy of the directed-lie test such that 86% of the innocent participants and 93% of the guilty participants were correctly classified.
Bell
Brian G
BG
Department of Educational Psychology, University of Utah, Salt Lake City, UT 84112, USA. brian.bell@ncl.ac.uk
Kircher
John C
JC
Bernhardt
Paul C
PC
D000328:Adult; D003198:Computer Simulation; D003415:Crime / Q000523:psychology*; D003417:Criminal Psychology; D008192:Deception; D005260:Female; D006167:Guilt; D006801:Humans; D008014:Lie Detection / Q000523:psychology*; D016015:Logistic Models; D008297:Male; D015203:Reproducibility of Results; D012119:Respiration; D012680:Sensitivity and Specificity