The literature on neuroimaging and its use in the courtroom is expanding furiously. Many legal scholars are weighing in on its uses, particularly on its possible use as a "magic cure" as a lie detector. Here's what Jennifer Bard, of Texas Tech University School of Law, thinks of neuroimaging scans and their use as evidence.
Jennifer Bard, Texas Tech University School of Law, A Call for a Moratorium on the Use of Information Derived from Neuroimaging as a Truth-Verifier in U.S. Courts.
Any law student who has taken Evidence has read about, or better experienced, an experiment in which a man bursts into a crowded classroom, runs through shouting and then leaves. When questioned directly after the event there is strong disagreement among the witnesses as to what the man was saying, what he was wearing and whether or not he had a gun. Based on the work of psychologist Elizabeth Loftus, now on the faculty of the University of California at Irvine Law School, this experience, more than any dry article about cognitive science, demonstrates the inherent unreliability of human memory and the conviction of eye-witnesses about what they have seen. Lawyers involved in the Innocence Project which is seeking to challenge wrongful convictions based on eye-witness testimony by examining conflicting DNA evidence have further brought these findings to public attention. As they explain, 'Research shows that the human mind is not like a tape recorder; we neither record events exactly as we see them, nor recall them like a tape that has been rewound.' Yet despite what has become common knowledge about the malleability of human memory, the idea that it’s possible to access the brain directly to find out whether a witness is telling the truth is being put forward by companies which seek to profit from research that suggests that new imaging technology can detect when a human is telling a lie. These companies are advertising this technology as a tool for law enforcement and promoting its use in U.S. trials as a way of helping juries to assess the credibility of witnesses.
This article explores these claims that neuroimaging scans can be used to detect lies, which far exceed those made by responsible scientists, and also puts them in the context of a series of U.S. Supreme Court cases which have dramatically changed how scientific (forensic) evidence can be presented to the jury in criminal trials. See Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S.Ct. 2786, 125 L. Ed. 2d 469 (1993) (establishing new criteria for admission of scientific evidence); Crawford v. Washington, 541 U.S. 36 (2006) (requiring that defendants directly face accusors). It also addresses the significant criticisms being brought against what has often been incautious adoption of unreliable techniques. 'Strengthening Forensic Science in the United States: A Path Forward' (National Research Council 2009).
In this article I argue that promises of lie detection are not only based on false premises, but they are harmful to the integrity of the legal system because they seek to substitute a technology, which is not just undeveloped and inadequately tested but inherently flawed, for the judgment of the fact-finder, judge or jury, in a criminal trial. I conclude that even if there was neuroimaging technology which could provide direct access to human thought, the result would share the inaccuracies and subjectivity that we already know is an inherent feature of human memory. Moreover, because this technology promises to do something that jurors know they cannot - determine when a person is lying - there is a substantial risk that it will prejudice defendants because jurors will substitute the results of the technology for their own collective judgment.
Download the full text of the paper from SSRN at the link.