By Erica Westly | May 13, 2010
Last week, a Brooklyn judge had the good sense to prevent a lawyer from using fMRI scans as evidence in a civil suit. But, as Wired bloggers report, new cases are already popping up.
For whatever reasons, the focus has been on using fMRI for lie detection. I find it hard to believe this will ever be scientifically acceptable, but that’s largely because I don’t think there will ever be a scientific method for determining whether or not someone is lying. Despite its popularity in movies and TV shows, the polygraph was never accepted by the scientific community, and there is no reason to believe that lie detection via fMRI is any more credible.
But does that mean fMRI scans should never be used in court? Not necessarily. After all, fMRI technology wasn’t developed for lie detection. Neuroimaging, including all types of MRI and PET scans, is primarily used to understand brain anatomy and function.
Researchers have used neuroimaging to identify brain differences in a variety of disorders, including schizophrenia, autism, and bipolar disorder, and I see no reason why fMRI scans shouldn’t be admissible in court in this capacity. This especially goes for sentencing hearings, where psychiatric diagnoses often serve as mitigating factors.
Of course, this idea is not without controversy, but that has less to do with the credibility of fMRI data and more to do with psychiatric defenses in general. For example, last fall a defense lawyer attempted to use fMRI scans (coupled with testimony from the diagnosing clinician) to get his client’s murder sentence reduced. In this case, the problem was not so much the use of fMRI as evidence as it was the psychiatric diagnosis itself: psychopathy, a controversial disorder that is not yet listed in the Diagnostic and Statistical Manual (DSM) and is not readily treatable.
The jury wound up upholding the defendant’s death penalty sentence in that case, but had the diagnosis been more traditional–say, schizophrenia–the results might have been different.
There’s been a lot of talk lately about how the utility of neuroimaging, particularly fMRI, is overhyped. The critics argue such “unproven” technology shouldn’t be allowed in the courtroom.
But it’s important to remember that a lot of the scientific technology already used in court is on even more shaky ground these days. Last year, the National Academy of Sciences issued a report calling for an overhaul of forensic science practices. Researchers have found serious problems with pretty much all the techniques you see on CSI: fingerprint analysis, handwriting analysis, burn pattern analysis in arson investigations.
Obviously, two wrongs don’t make a right, but the point is we shouldn’t act like the bar for science in the courtroom is somehow higher than in academia. Moreover, the chances that fMRI scans will become a commonly-used form of forensic evidence are extremely rare. For journalists and scientists to treat the issue as if it’s this huge threat to the criminal justice system is a disservice to the public, in my opinion.