Putting Your Brain on Trial

A court in San Diego will soon be deciding whether to admit results from the newest version of lie detection.  The technology, called functional magnetic resonance imaging (fMRI), detects which areas of the brain are active by measuring changes in blood flow to different regions of the brain.  Proponents of the technique, mainly companies that perform the test to prove their client’s innocence, claim that by monitoring these changes in a person during questioning allows a determination of whether the person answered the question truthfully depending on which part of the brain is active.  Despite the fact that the companies advocate fMRI as a highly successful lie detector that cannot be tricked like the conventional polygraph test, even fMRI’s pioneer, Dr. Daniel Langleben, has serious doubts about these claims.  He correctly points out that there have been very few large-scale studies to determine the accuracy of the technique in detecting lies, and that there may be significant differences between an absence of deception and innocence.  Other fMRI researchers are equally skeptical about the accuracy of detecting deception using fMRI.  It may be possible to use advances in neuromarketing, which uses fMRI to monitor people’s responses to products and advertising without the possibility of false self-reporting, as a starting point for the reliability and accuracy of fMRI lie detection; this approach could get around the high costs of clinical trials needed to establish fMRI’s deception detection capabilities.

In the San Diego case, the defense plans to try to increase the probability of admissibility of its fMRI evidence by limiting the relevant scientific community to only those who are developing fMRI lie detection technology.  This limitation is biased in the extreme, and would allow unreliable scientific evidence into the courtroom due to the expert’s conflict of interest.  However, lawyers trying to keep evidence of results from a similar brain-based lie detection technology in India failed to get those results excluded, despite testimony from scientists showing that the technology was highly unreliable and thus should not be used in court.  Hopefully, courts in the United States will listen to testimony from unbiased scientific experts and treat fMRI lie detection with the skepticism it deserves.