Neuroscience and the Law

MRIs and similar neurological data is seldom used as evidence in trials, however they have the potential to reveal a substantial amount of information regarding a witness’s credibility and responsibility in the future. Functional MRIs measure the levels of oxygenated hemoglobin in the body that occurs when a part of the brain is particularly active. MRIs are essentially an indirect measure of neuronal activity, and provide images that describe somebody’s state of mind. This technology does not, however, measure the firing of brain cells directly, but rather deals with blood flow. In oder to define the imaging of a brain associated with a certain type of brain activity, the brain scan must be compared to an average of many scans. Thus, even though a defendant’s scan may appear vastly different from the average, it may still be well within the statistical average of brain activity.

Attorneys are beginning to ask judges to admit MRI data as evidence in order to demonstrate that a defendant is telling the truth or to dismiss accusations of insanity. While some judges accept this data because they believe it offers information that gives jurors a better understanding of an issue or salvages fruitless debates, other judges reject the data because they believe the scans would be too persuasive and carry too much weight due to their scientific nature. This has been a controversy in legal rooms, however the general consensus thus far has been that scans offer an unfair advantage to one side and carry with them prejudice. Furthermore, MRIs can only dismiss accusations regarding physical brain injury, and some criminal defense attorneys may introduce the scans in order to convince the jurors that the defendant is suffering from a cognitive or emotional disorder. The science of MRIs simply does not allow us to draw these conclusions as of yet.

Functional MRIs offer good scientific information, however very little of it is admissible in courts. For example, experiments using MRIs have proven that dishonest behavior is correlated with extra activity in certain brain regions which are involved in impulse control. Having date and images of this brain activity could be very useful in trials, as it could be a great indicator regarding the honesty of the defendant. However, most judges still refuse to accept this evidence. The main reason for this is that showing the brain scan of a defendant without a substantial amount of data from a similar population group would mislead a jury. Brain activity is not standardizes and scientists cannot predict the normal variations in brain anatomy. Judges already have a difficult task in evaluating whether psychiatric and similar disorders should be taken into account when discussing culpability. Allowing brain images, even highly informative ones, will only add to this challenge.

Another argument against accepting MRI evidence is that scientific advances have the potential of separating our brains and minds from our personal responsibilities. In the 2005 case Roper vs. Simmons, the US Supreme Court decided that no person younger than 18 at the time of the crime could receive a death penalty because juveniles are more susceptible to negative influences and suffer from immaturity. In 2010, it was decided that a person younger than 18 was also excused from a sentence of life without parole. Although it is true that those younger than 18 are more easily influenced and less capable to make a decision than an adult, it is also true that a person, and not a brain, commits a crime. Where does neurological data stop being useful and start being used as an excuse for a crime?

In my professional opinion, brain scans and similar data should be kept to a minimum in a court of law. While they do hold potential and in some cases would make issues clearer for jurors, the limitations and consequences of these technologies pose a greater risk.

2 responses to “Neuroscience and the Law”

  1. Madiha Shafquat says:

    I like how you’ve managed to come to a compromise between the potential use of fMRI as evidence and the limitations of the technique. I agree that they should perhaps be used only to strengthen arguments, rather than make them.

  2. Brianna Margaret Cathey says:

    That’s interesting you bring up the idea that the imaging may be used as an excuse for the crime. I hadn’t explored that angle as fully. I do agree that the use of fMRI too often may sway the jurors to make a faulty conclusion about the level of personal responsibility held by the defendant.

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