Neuroimaging in the Courtroom
|from Scientific American blog
Recently, an article by Martha Farah and Cayce Hook2 took a critical look at the two studies that are most frequently cited as being evidence for neuro-realism and discussed why this theory has continued to persist despite its lack of evidence. The first study by McCabe and Castel3 analyzed whether people consider scientific findings more believable when accompanied by functional brain images, and the collected data suggested that scientific reasoning in research descriptions made more sense to participants when a brain image was provided as evidence. However, Farah and Hook point out that these brain images are actually more informative than a bar graph or topographic map, and participants should find them more compelling. The second paper often cited in relation to neuro-realism is a study by Weisberg, et al.4 which asked participants to consider whether an explanation for a psychological phenomenon, which did or did not include irrelevant neuroscientific rationale, was good or bad. Participants that were not neuroscience experts were more likely to rate a bad explanation as favorable when accompanied by neuroscience data. This study, however, did not include images, and even the authors of the paper admit that people may respond in a similar fashion to information that comes from specialties outside of neuroscience and psychology; there could be a general fascination with science that makes poor explanations appear reasonable. Farah and Hook also highlight a number of experiments5-7 that have been unable to replicate the findings from these two studies, helping to cast a shadow of doubt on neuro-realism.
Whether or not we really are unnecessarily enthralled by brain images is still out for debate, but is neuro-seduction real in the courtroom when neuroimaging is presented as evidence? This is relevant because a study by Bright and Goodman-Delahunty 8 found that mock jurors presented with gruesome and neutral images of a crime scene convicted defendants at a significantly higher rate than jurors that were not exposed to any images. These results beg the question that if a neutral image can provoke a response, then what is the effect of an image of a brain? Schweitzer et al.9 conducted four experiments in an attempt to determine the effect of neuroimaging in cases involving the mens rea defense where jurors did not need to decide whether a defendant was guilty or not, but instead whether or not the defendant possessed the mental state to be guilty. In brief, researchers found that neuroimages had no significant effect on the proportion of guilty verdicts or sentence recommendation length compared to other types of evidence for a neurological defect (specifically a defect in the frontal lobe). The mock jurors were either subjected to evidence of neurological damage that could render the fictional defendant unable to have mens rea in the form of a clinical psychiatrist describing behavioral traits, a clinical neurologist who identified brain damage based on a physical exam, a neuroscientist only describing a neuroimage that was not presented, a neuroscientist describing brain injury accompanied by a graph, and a neuroscientist describing injury accompanied by an image of the brain. Interestingly, when jurors judged the responsibility of the defendant, those who heard testimony from a clinical psychiatrist actually judged the defendant to have to more control over his actions than those that were exposed to neuroscientific testimony in any form. The only significant finding from the experiments was that neurological data – that which included images and that which did not – was more persuasive than data from a clinical psychiatrist when judging responsibility, but this judgment did not translate during the conviction and sentencing phase of the mock trial.
How relevant is neuroimaging in the courtroom based on the results? According to Stephen J. Morse in a recent AJOB Neuroscience article,10 neuroimaging has very little relevance in cases that require judges and jurors to evaluate the mental capacity of a defendant, and this view is supported by the findings from the experiments conducted by Schweitzer et al.9,11 While there may be less bias toward neuroimages than was initially believed, neuroscience and neurotechnologies are constantly evolving. Brain scans require the viewer to make a reverse inference, which is to “infer the engagement of particular cognitive functions based on activation in particular brain regions.”12 This requires reasoning backwards, and an example of this would be that low activity in your frontal lobe area means you are psychopath. This assumes though that specific brain activity can be directly correlated to thoughts, behaviors, or tendencies, and we know that obtaining and interpreting the images is much more complicated. At this time it is probably reassuring that juries do not appear to take brain scans more seriously than other factors in cases where neuroimaging could help to provide evidence of intent. However, there could be a time in the future when neuroimaging can provide more compelling evidence than only expert testimony and at that time it may be reasonable to assume that neurological data could not be faked. In this future scenario, neuroimaging should play a larger role in sentencing and convictions, but we are not there yet. There is still much to consider when it comes to neuroimaging, but neuroscientists must work with lawyers, judges, and the media to ensure that neuroscientific findings and results are appropriately applied to courtroom scenarios.
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Strong, K. (2015). Neuroimaging in the Courtroom. The Neuroethics Blog. Retrieved on
, from http://www.theneuroethicsblog.com/2015/02/neuroimaging-in-courtroom.html