Neuroscience and the Law

Currently, neuroscience technology is being developed at a faster rate than ever before. While it seems that these recent developments are designed to diagnose neurological problems or to help people overcome neurological challenges, many people do not realize the alternate use of neuroscience technology in a court of law.

In the past, polygraphs were frequently used in court, detecting changes in blood pressure, pulse, skin conductivity, and respiratory rate. Erratic changes in these measurements were thought to indicate lying. However, people can learn to keep calm to “trick” the test, rendering the polygraph inaccurate. More recently, CT scans and MRIs have been used as evidence in courts. CT scans and MRIs can show abnormalities in the brain. For example, the CT scan of the brain of John Hinckley Jr, the man to attempted to assassinate President Reagan, showed “slight brain shrinkage and abnormally large ventricles”. The defense lawyers stated that this was indicative of a mental defect, though the prosecution claimed the scans were normal. In addition, a structural MRI looks at the static structure of the brain, and has been used to diagnose disorders like schizophrenia, for example.

The most recent piece of neuroscience technology to make its way into the court is the fMRI, functional magnetic resonance imaging. The fMRI looks at areas of blood flow in the brain to detect areas of activity during cognitive control, attention, and moral decision making tests. This has been used in place of a polygraph, as it is thought that frontal lobe activity can indicate lying, in addition to activity in the areas of the brain that are involved in impulse control and decision making. Also, the fMRI has shown that the brains of psychopaths show distinct defects in the paralimbic system that controls memory and emotion. fMRI scans have been shown in court so that the defense could plead insanity. One example of this is the case of Brian Dugan, a man who had raped and murdered women and young girls. His fMRI scan was presented in court, and the defense could use it to claim that “Dugan is a psychopath and could not control his killer impulses”.

Though the fMRI seems like an accurate, reliable piece of neuroscience technology, it has far more points against it than for it. The fMRI detects activity based on blood flow, but it has nothing to do with the activity of neurons. If it cannot show or measure the firing of brain cells, how do we know that blood flow is an accurate predictor of neuronal activity? The fMRI is rarely used in diagnosis, so it cannot be used to prove that someone is schizophrenic or a psychopath, for example. A recent fMRI scan does not necessarily indicate anything about a person’s mental status at the time he or she committed the crime, so, again, in court, it cannot be used to prove that the person was experiencing a mental health episode. Most importantly, it is very difficult to interpret the results of an fMRI for one single case. When studying fMRIS, neuroscientists look at average differences between different groups of people; showing a single fMRI during a court case would be very misleading. The fMRI is in no way reliable or accurate enough, at this time, to be used in legal settings.

Some lawyers may claim that neuroscience technology should undoubtedly be used in court. It can show patterns of brain activity or brain processes that can identify a person’s altered mental state. They believe that it is scientific proof, and should be treated as any other piece of evidence. However, for this exact reason, neuroscience technology should not be used as evidence in court. It may be used to make the defense look impressive, easily misleading a jury. In addition, if members of the jury do not have an understanding of this technology, for example how one single fMRI scan is almost irrelevant, they can also be misled. Perhaps, in the future, as more neuroscience technology becomes available, and existing neuroscience technology becomes more accurate and reliable, it can be reintroduced into courts. For now, however, neuroscience technology should be left out of the courts.

One response to “Neuroscience and the Law”

  1. Hannah Bukzin says:

    I 100% agree. I think that as neuroscience technology increases, that is the time to reintroduce it back into the court. But, at the moment, fMRI’s should not be allowed to be used as evidence.

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