Have you ever wondered about the methodologies behind lie detection? Is its application in the courtroom setting appropriate? In which cases is lie detection machinery flawed? A Monday night panel discussion held by the Stanford Interdisciplinary Group in Neuroscience and Society (SIGNS) attempted to tackle these issues, covering modern neuro-imaging in locations outside the lab.

The event, “Neuroscience in the Courtroom,” debated the merits of lie detection testing, concluding that there were significant reasons to regard it with skepticism. The panel commenced with a brief introduction of potential and current uses of neuro-imaging in today’s society. Those uses included prediction of behavior, ability to read minds, detection of pain, criminal responsibility, treatment of such diseases as Alzheimer’s and enhancement of neural processes through drug use. The discussion then progressed to the perspectives of a law professional and neuroscientist on the use of neuroscience in the court.

Two mediums for lie detection have been especially involved in court cases both past and present: The polygraph and functional Magnetic Response Imaging (fMRI). Recently, MRIs were used in court to attempt to prove a plaintiff’s innocence when he claimed that he hadn’t committed fraud against the government. Another case used an MRI to confirm a woman’s claim that a man had domestically abused her. In both cases, the judges did not allow the evidence. Early cases like these bring the use and appropriateness of neuro-imaging and neuroscience evidence in court into question, the panelists said.

Anthony Wagner, panelist and cognitive neuroscientist, discussed the reliability of different forms of lie detection. In doing so, he partially justified the skepticism of judges and other court personnel in allowing lie detection as evidence in court cases.

“As of now, there is no relevant data on the sensitivity and specificity of fMRI-based lie detection,” he said.

Rather, the studies compare the condition of lying with telling the truth, and at times subjects repeat stories to the lie detection test to seem as if they are telling the truth. Ultimately, there are many different factors for which lie detectors test, including deception, memory and salience of stimuli, but because these tests are ambiguous, it is understandable why their use as evidence is questionable.

Hastings law professor David Faigman gave the legal-side opinion on the issue and began with an introduction of the general criteria used for admission of evidence: qualifications, relevance, reliability and validity.

In assessing these criteria, a judge looks at how much testing has been done in the science presented in the evidence, peer-review and general acceptance in society. Federal Rule 403, which says, “If probative substance is outweighed by unfair prejudice, the evidence is not to be used,” is often applied to neuroscience evidence.