The judge in the Tennessee case that might have used functional MRI (fMRI) scans as part of the case has excluded such evidence. The opinion is not yet available online, but reports indicate that the judge considered the fMRI tests (to assess the credibility of a witness) to fail several prongs of the Daubert test, which determines whether or not certain evidence is permitted in Federal court. The Daubert test is different from the Frye standard that was relevant in the New York case concerned with fMRI evidence. The Daubert test is more explicitly scientific. Scientific evidence can be admitted if the judge determines that the following hold true:
- The theory or technique can be, and has been, tested;
- Said theory or technique has been subjected to peer review and published;
- There is a known or estimated potential error rate;
- Has the theory or technique been generally accepted by the scientific community
The judge criticized fMRI testing as not repeating ‘real-world’ situations, where the kinds of consequences were on the line that would be the case in a trial situation. If the science behind the scans were more developed and accepted, he could see possibly accepting the technology independent of ‘real-world’ testing. However, his assessment was that the scientific community had not accepted the technology for use in courts. There were also concerns about the specific methodology used in this case that raised doubts about the ability of the scans to produce consistent results.
At the moment, it looks like brain scans for truth-telling will remain a part of science fiction. That may change in the future, but there’s a lot of work to accomplish before that happens.
