Kent Kiehl, a neuroscientist at the University of New Mexico, has spent decades scanning prisoners' brains to identify psychopathy. His research, which he claims can predict violent behavior, has been used in thousands of US criminal cases, often by defense attorneys seeking lighter sentences. But critics argue the science is unreliable, ethically dubious, and echoes discredited eugenic theories.
Kiehl's Rise and the Dugan Case
Kiehl first gained notoriety in 2009 when he testified in the case of serial killer Brian Dugan. Dugan had confessed to the rape and murder of a 10-year-old girl, and his attorneys hoped brain scans showing psychopathy would spare him the death penalty. Kiehl testified that Dugan's psychopathy checklist score was in the highest range he had ever seen, and that fMRI scans showed his brain was atrophied. Despite this, the jury sentenced Dugan to death, though his sentence was later commuted to life in prison after Illinois imposed a moratorium on the death penalty.
Kiehl's testimony marked one of the first US court cases to admit brain research as evidence. In the following decade, the use of such evidence exploded. A 2019 study found that from 2005 to 2015, brain evidence appeared in more than 2,800 judicial opinions, with neurological arguments for reduced criminal responsibility appearing in roughly 10-12% of US murder trials and about 25% of death penalty trials.
The Amos Wells Case
One of the most troubling examples is the case of Amos Joseph Wells III. In 2013, Wells shot and killed his pregnant girlfriend, her mother, and her 10-year-old brother in Texas. He then turned himself in, showing signs of remorse and psychosis. At trial, his own defense attorneys used Kiehl's company, Mindset, to conduct brain scans and genetic tests. They argued that Wells had a variant of the MAOA gene, sometimes called the "warrior gene," which predisposed him to violence. The prosecution used this same evidence to argue that Wells would always be dangerous, and the jury sentenced him to death.
Dr. Jolie Brams, a psychologist who worked on Wells's defense, said the focus on biology ignored his traumatic childhood, which included sexual abuse, violence, and poverty. "Environment forms the brain," she said. "Once you start talking about determinism, like genetics, that gets to be very iffy, because people start to wonder, 'Would that person ever be different?' And that is probably the worst thing you can do in a capital case."
Criticism from Scientists
Many scientists have criticized Kiehl's work. Satrajit Ghosh, a neuroscientist at MIT, called predicting behavior from brain scans "extreme sci-fi." Stephen J. Morse, a legal scholar at the University of Pennsylvania, described Kiehl as a "vast brain overclaimer." Even a 2018 paper by Kiehl and colleagues was retracted in 2019 due to errors in data analysis.
Sociologist Oliver Rollins notes that prison populations are shaped by racism, so brain studies conducted in prisons disproportionately study people of color. "If you're not going to engage in these kinds of ethical questions, then how do we make sense of the ethics of this particular type of work?" he said.
Kiehl's Defense
Kiehl defends his work, saying it is peer-reviewed, publicly funded, and goes through rigorous ethical review. He has received over $41 million from the National Institutes of Health since 2005. He acknowledges that the criminal justice system is biased, but says it is biased toward people of low socioeconomic status, not race. Data shows that Black people are more than five times more likely to be incarcerated in Ohio than white people, contradicting his claim.
Kiehl also runs a for-profit company, Mindset, with his wife, which has been involved in over 200 capital cases. He said he had to stay behind the scenes due to conflicts of interest.
Wells's Appeal
Wells's new attorneys, from the law firm Cooley LLP, have appealed to the U.S. Supreme Court, arguing that his trial was tainted by pseudoscience and racism. They have been supported by the NAACP and 29 scientists and lawyers. Matthew Kutcher, a partner at Cooley, said: "If you tell a jury that a Black man is genetically wired for violence, you're inviting them to see him through racist stereotypes, not as an individual."
Wells remains on death row. His case highlights the profound stakes of using disputed brain science in court, where an illusion of scientific certainty can lead to a death sentence.
