Keep your head on—examining the heated debate on the use of neuroscience in the courtroom

“A lawyer’s performance in the courtroom is responsible for about 25 percent of the outcome; the remaining 75 percent depends on the facts.” –Melvin Belli

Illustration courtesy of Brian Patterson.

The recent surge in the use of neuroscientific evidence in the courtroom has caused an uproar in both the scientific community and in the nation at large. Many scientists decry the utilization of brain scans as a “dangerous distortion of science” and warn against all such use. Others argue that our understanding of neuroscience is still minimal and that it is too early to begin using such evidence in a practical way, especially in cases of life-and-death, as is often the case in criminal justice cases. Still others accuse neuroscientists of using powerful biological data to dazzle and sway naïve jurors and judges into supporting their position. Such arguments lead to the inevitable question—should neuroscientific findings be banned from the courtroom?

Not necessarily, argues psychologist Ruben Gur, who has testified in over thirty criminal cases throughout his career, including that of the infamous Unabomber, Ted Kaczynski. Gur uses PET scans to determine if the defendants have a form of mental illness, like schizophrenia, and is a strong proponent of using brain scans in the courtroom.  He contends that other forms of biological testimony, such as fingerprint analysis and DNA testing, are embraced in the courtroom. Why is neuroscientific evidence not treated with the same level of support?

PET scans of normal and schizophrenic brains.

Deborah Denno, a psychology and law professor at Fordham Law School, agrees with Gur, pointing out that not only are other forms of biological evidence being used without controversy, but that other discredited forms of evidence continue to be used in the courtroom today. Consistent evidence has found that eyewitness testimony is highly unreliable in determining culpability; yet such testimony remains popular in courtrooms. Denno also argues that the majority of the arguments against the use of neuroscience are based on mere hypotheticals, and that there is no actual evidence that such neuroscientific data has been used in the ways that critics are suggesting. There is little evidence to suggest that neuroscientific data is used to get criminals “off the hook” or as proof of "further dangerousness." Basing the argument against neuroscience in courtrooms solely on abstract theoretical points is dangerous, and constructs a barrier against future attempts at trying to use neuroscientific data in a practical way.

Accusations that neuroscientists take advantage by throwing impressive-looking brain scans at jurors and juries to dazzle them into submission may also be ruled out. Aside from the fact that such an argument disparages the intelligence of jurors at large, Denno and her colleagues have found that jurors are far more resilient to the so-called "Christmas Tree Effect" than their opponents suppose. She also points out that prosecutors often use visually jarring images to support their case. This is an important inconsistency that many opponents of neuroscience in courtrooms conveniently neglect to mention.

 

Basic functions of parts of the brain [Credit: Elizabeth Traynor].

What, then, is the cause of this vehement refusal to accept neuroscientific evidence as valid forms of proof in the courtroom? Is it a fear that these criminals, many of whom have committed unspeakable crimes, will get off scot-free? Such a fear is certainly understandable. However, the purpose of using brain scans in the vast majority of these cases is not about whether the culprit is guilty. Rather, it is most often used to determine whether the defendant should be given the death penalty.  It would enable a person who suffers from mental illness to not be unduly punished for his or her crimes. Understanding this key difference is vital to understanding how and why neuroscience is being used in the courtroom, and that the practical benefits of the judicious use of brains scans outweigh the potential negatives.

The arguments against using neuroscientific evidence are as diverse in nature as they are in validity. Given historical abuses of biological evidence, it is natural to be wary of the potential misuse of neuroscience in the courtroom. However, we must also be careful not to be too hasty to reject all use of neuroscientific findings. Such a step would be a terrible mistake, and would lead to the loss of a potentially powerful tool in criminal justice.

References:

Deborah Denno. “The Impact of Neuroscience on Criminal Law Cases across Two Decades, 1992-2012.”  Loyola University Chicago, Brain Matters—Neuroscience in Criminal Law and Policy Colloquium. Chicago. 26 Sept. 2013.

Ruben Gur. “Neuroscience in the Courtroom: Too Early, Too Late, or Just in Time?” Loyola University Chicago, Brain Matters—Neuroscience in Criminal Law and Policy Colloquium. Chicago. 26 Sept. 2013.