Neuroscience and the Law

There has been much debate over whether or not brain scans and other neurological “evidence” should or should not be allowed. This debate is being fought on many different fields of science and within the jurisdiction system itself. Generally speaking, prosecutors are against the use of these scans in the court room as the jurors could be swayed in the direction that the defense is trying to show due to the stigma surrounding scientific “facts.” Scientific evidence such as scans will be highly appealing to the jurors and/ or judge. The defense attorneys are generally in favor of the use of these same scans for the same reasons listed above as to why prosecutors do not necessarily approve of them.

The most common neurological scans that are attempted to be placed into evidence by the defense attorneys (or maybe prosecution attorneys) are Functional Magnetic Resonance Images (fMRIs) and lie detector test results. Lie detection is based off of the blow flow, heart rate, and many other factors measured by a machine as the person being interrogated is answering questions. fMRIs work by placing a subject into the machine that tracts the blood flow within the brain between specific areas that are thought to correlate with specific function and actions.

The use of lie detectors has been dismissed for many years for the mere fact that the signals and other signs being measured can be controlled by the subject or influenced by the situation. If you can control your heart rate and breathing you may be able to trick the test; similarly, if you are nervous or stressed out, the machine may read what you are saying as a lie if it is in fact a truth. fMRIs cannot say definitively whether or not the disruption in blood flow is caused by activity in that brain region. They also do not give definite answers on whether or not the subject has a mental disorder that would affect his judgments and actions.

That being said, the use of them as evidence is not completely unjustified. Although they do not give perfectly accurate, definitive answers they can be used for a general judgment. Take the fMRI for example, it may not be able to show if each question answered is being answered truthfully, but it can show if the person was, in general, being honest. They can show if there is a malfunction or structural impediment that the person has that may have influenced his or her actions.

Personally, in the debate of the legal use of neurological scans and images, I would advise against it. I do not believe that the technology is advanced enough to give us the definitive answers that should be required by the courts. Once scientists are able to look at a scan, and say with almost no doubt that a subject, defendant, person, has something wrong with them that made it impossible for them to resist the urge to do what they did, then the use of these scans will be completely validated. Although they can provide reasonable doubt, is that because the jurors are easily swayed by the scientific look of the scans or the evidence they may or may not prove?

2 responses to “Neuroscience and the Law”

  1. Fabiana Vilsan says:

    I agree that fMRIs are not completely reliable forms of evidence.

  2. Swathi Srinivasan says:

    I too agree with the statement about fMRI scans, unless paired sMRIs , it does not have excellent spatial resolution.

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