Simple, effective countermeasures to P300-based tests of detection of concealed information.
We found countermeasures to protocols using P300 in concealed information tests. One, the "six-probe" protocol, in Experiment 1, uses six different crime details in one run. The countermeasure: generate covert responses to irrelevant stimuli for each probe category. Hit rates were 82% in the guilty group; 18% in the countermeasure group. The average reaction time (RT) distinguished these two groups, but with overlap in RT distributions. The "one-probe" protocol, in the second experiment, uses one crime detail as a probe. Here, one group was run in 3 weeks as a guilty group, a countermeasure group, and again as in Week 1. COUNTERMEASURE: Covert responses to irrelevant stimuli. In Week 1, hit rate was 92%. In Week 2, it was 50%. In Week 3, 58%. There was no overlap in the irrelevant RT distribution in Week 2: Countermeasure use was detectable. However, in Week 3, the RT distributions resembled those of Week 1; test-beaters could not be caught. These studies have shown that tests of deception detection based on P300 amplitude as a recognition index may be readily defeated with simple countermeasures that can be easily learned.
Rosenfeld
J Peter
JP
Department of Psychology, Northwestern University, Evanston, Illinois 60208, USA. jp-rosenfeld@northwestern.edu
Soskins
Matthew
M
Bosh
Gregory
G
Ryan
Andrew
A
D000328:Adult; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D006801:Humans; D008014:Lie Detection; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D009042:Motivation; D010865:Pilot Projects; D011930:Reaction Time / Q000502:physiology