Scanning for murder raps

Nature has a freely available feature article that discusses recent debates about how functional brain scans should be used in court cases concerning people charged with murder and classified as psychopaths.

Brain scans that show an estimate of brain activity, such as fMRI, are widely used in forensic and medical research to understand whether offenders and psychopaths differ in how their brain processes information.

These studies usually rely on group differences, showing that, on average, brain activity occurs differently in offenders compared to non-offenders, patients compared to non-patients and so on.

Court cases, of course, attempt to decided whether a single individual is criminally responsible for his or her actions. Inferring individual differences from broad group averages is difficult, some say impossible but despite this, functional neuroimaging is being increasingly used in court.

The Nature article discusses the recent Jeanine Nicarico murder case where Brian Dugan was being charged (and later confessed to) with the young girl’s murder.

Controversially, and for the first time in the US, the court was permitted to see evidence from functional brain scans from neuroscientist Kent Kiehl related to Dugan’s diagnosis of psychopathy.

On 29 October, Kiehl participated in a ‘Frye hearing’ for Dugan’s case. Based on a 1923 ruling, the hearing determines whether scientific evidence is robust enough to be admitted. Joseph Birkett, the lead prosecutor in the Dugan case, argued that allowing the scans ‚Äî the bright colours and statistical parameters of which are chosen by the researchers ‚Äî might bias the jury. Some studies, prosecutors argued, have shown that neuroscientific explanations can be particularly seductive to the layperson.

The judge ultimately “cut the baby in half”, says Birkett. He ruled that the jury would not be allowed to see Dugan’s actual brain scans, but that Kiehl could describe them and how he interpreted them based on his research.

According to the article, the scans had a significant influence on the case and it has raised a heated debated about whether such evidence is possibly interpretable in legal terms.

Neuroscientists are typically harshly critical about lawyers’ enthusiasm for wanting to use less-than-clear cut technologies like ‘brain scan lie detectors’ in court.

However an article recently published in Trends in Cognitive Sciences was very critical of this attitude, noting that the court’s requirements were often different from science’s, and than even suggestive evidence could help fill out the overall picture, and hence it was up to the court to decide whether such evidence should be admissible, not scientists.

Nevertheless, these sorts of arguments raise the hackles of many researchers and neuroscientist Helen Mayberg is quoted in the Nature piece as saying “It is a dangerous distortion of science that sets dangerous precedents for the field”.

The article is great coverage of the particular case and an interesting look into how neuroscience research is being uncomfortably integrated into the legal system.

Link Nature article ‘Science in court: Head case’ (via @mocost).

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