A scientist says he can scan prisoners' brains for signs of evil. Did his disputed science put a man on death row?

[erronis]

https://www.theguardian.com/us-news/ng-interactive/2026/jun/23/scientist-us-legal-system-violence-brain
Sarah Hopkins

Kent Kiehl convinced the US legal system he can find violence in prisoners' brains. His theories have been since used by defense lawyers - with grave consequences for prisoners



Too much information to easily excerpt in four paragraphs. Please read the article if you are interested.

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Dugan's trial, 17 years ago, was one of the first US court cases to admit brain research as evidence. The case made national news. But Kiehl's evidence didn't convince jurors to be lenient. They sentenced Dugan to death. His sentence was later commuted to life in prison, only after the state of Illinois imposed a moratorium on the death penalty.

But what happened in the aftermath was seismic. In the years that followed Kiehl's testimony, the science of biological criminality, though shaky, was invoked in thousands of cases. Defense attorneys, in particular, used biological evidence like brain scans to argue that their clients should receive lighter sentences.

From 2005 to 2015, the use of brain evidence in criminal defenses appeared in more than 2,800 judicial opinions, according to a 2019 study. The researchers estimated that neurological arguments for reduced criminal responsibility appeared in roughly 10-12% of US murder trials, about 25% of death-penalty trials. Overall, 40% of serious felony cases referred to brain-based evidence.

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The stakes are profound. A body of science that many researchers describe as unreliable has now become routine in capital cases. In US courts, this illusion of scientific certainty has led to some defendants being sentenced to death.

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