The Influence of fMRI Lie Detection Evidence on Juror Decision-Making


  • Department of Psychology, Colorado State University.

  • David P. McCabe died unexpectedly on January 11, 2011. He was a brilliant collaborator and true friend, and will be missed.

Alan D. Castel, Department of Psychology, University of California, Los Angeles, 1285 Franz Hall Box 951563, Los Angeles, CA 90095-1563.



In the current study, we report on an experiment examining whether functional magnetic resonance imaging (fMRI) lie detection evidence would influence potential jurors' assessment of guilt in a criminal trial. Potential jurors (N = 330) read a vignette summarizing a trial, with some versions of the vignette including lie detection evidence indicating that the defendant was lying about having committed the crime. Lie detector evidence was based on evidence from the polygraph, fMRI (functional brain imaging), or thermal facial imaging. Results showed that fMRI lie detection evidence led to more guilty verdicts than lie detection evidence based on polygraph evidence, thermal facial imaging, or a control condition that did not include lie detection evidence. However, when the validity of the fMRI lie detection evidence was called into question on cross-examination, guilty verdicts were reduced to the level of the control condition. These results provide important information about the influence of lie detection evidence in legal settings. Copyright © 2011 John Wiley & Sons, Ltd.