Brain scan lie detection knocks on the court doors

Wired Science interviews a professional observer in the most important legal hearing for the use fMRI brain scan ‘lie detection’ technology yet to come to court.

The observer was Owen Jones, a professor of law and biological sciences at Vanderbilt University, and the hearing was over the scientific status of ‘lie detection’ scans done by commercial company Cephos and are been touted by the defence in a case of someone accused of defrauding medical insurance in the US.

The debate is over whether the technology reaches the Daubert standard, criteria for whether scientific testimony or a specific technology is considered reliable enough to be admissible as evidence.

The case is interesting in light of the discussion we covered about the variety of possible legal uses of fMRI, as the lawyers wanting the evidence admitted are not wanting to use it as a straight-forward truth test about something that did or did not happen in the external world.

But rather, whether the accused is telling the truth about their earlier intentions. In other words, it’s a question of their honesty about an earlier mental state. Is there anything special about the way the defense is trying to use fMRI in this case?

Jones: One of the things about this case that has gone undernoticed is that even though fMRI lie detection has not yet been admitted, the purposes for which people are seeking to admit it are already rapidly evolving. In this case, the defense is not attempting to introduce fMRI lie detection for purposes of verifying what was at some past time an external state of the world as, for example, when a hypothetical defendant says he was in his house at the time of the alleged murder. That would be a natural context to use lie detection. You’d ask, “Were you home? Are you lying?”

In this case, the defense is taking it to the meta-level. They are using a scan as evidence of a person’s prior state of mind. What’s at issue is whether the defendant knowingly and willfully did what he did. The defense is therefore attempting to offer fMRI to demonstrate his past state of mind. The report actually says, “Doctor Semrau’s brain indicates he is telling the truth in regards to not cheating or defrauding the government.” It means that we’re introducing evidence of the brain’s current assessment of the brain’s former mental state. That’s one of the things that makes it tricky. He’s trying to have his brain testify as to the prior state of his brain.

For fMRI to have already reached that level of complexity in the first case in which there has been a Daubert hearing gives some indication of how much more future litigation there is likely to be in this arena.

Although it seems a great deal of scientific evidence was presented by both sides, as far as I can make out, the type of ‘lie detection’ scanning done in this case deviates so far from the standard (and still not very reliable) lab procedure that the main thrust of the argument to have the scans admitted seems to be ‘oh, go on!’

Link to Wired Science on ‘Watershed’ Legal Hearing (via @edyong209)

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