Introduction
In recent years, the interdisciplinary field of neurolaw has begun to emerge and reshape the legal world. This field has begun to incorporate findings in neuroscience with their many implications in legal contexts in an attempt to better the accuracy of legal proceedings.
Neuroscience Background
Within the world of neuroscience, there are many tools and assessments used for a plethora of purposes. As of now, the two types of imaging that are pertinent in neurolaw are PET scans and MRI scans. A PET scan, or positron emission tomography, is a test that uses radiation to measure metabolic activity within the body. This procedure mainly detects biochemical changes within organs and can therefore be used to see the onset or progression of many different diseases. This type of scan is particularly helpful to neurologists, cardiologists and oncologists in identifying malfunctions in both structure and function of organs. One benefit to PET scans is that they can often detect things before other tests can, making them very valuable in preventative and early intervention measures. Often PET scans are used in conjunction with CT (computer tomography) scans in order to get a full picture.
The second type of test used in neurolaw is an MRI, or magnetic resonance imaging. MRI scans use magnetic and radio waves in order to create a picture of a specific part of the body (whatever it is focused on). The MRI machine is essentially a giant magnet, and the magnet causes the protons in the body to line up in the same direction. The signal given off by the protons returning to their normal position is picked up by receivers, which in turn creates a picture. MRI scans have been found to be particularly helpful in looking at the nervous system and soft tissue injuries, and can be used to view structural abnormalities, brain injuries, stroke and cancers. In addition, a specific type of MRI known as fMRI (functional MRI) can be used to study brain activity, as it looks at blood flow to the brain and the activity of different parts of the brain during different tasks.
Legal Background
In order to be admissible in court, all evidence must adhere to either the Daubert standard or the Frye Standard, depending on where the court proceeding occurs. The Frye standard was enacted after Frye vs United States in 1923, and is used to “determine whether or not the method by which that evidence was obtained was generally accepted by experts in the particular field in which it belongs”. In 1993, the Frye Standard was replaced in federal courts with the Daubert Standard, which is the “standard used by a trial judge to assess whether an expert witness’s scientific testimony is based on scientifically valid reasoning that which can properly be applied to the facts at issue”. At this time, the Daubert standard is used in federal court as well as many state courts, however the Frye standard still exists in several states. In the case of brain imaging, courts often rely on expert witnesses to explain the tests and results to the laymen of the jury. Therefore, as long as the expert witness has sufficient credentials and relevant experience, brain imaging and its interpretation can be entered as evidence under the Daubert Standard.
In addition, it is important that any evidence meets the conditions laid out in the Federal Rules of Evidence. The Rules are based on several principles aimed at regulating evidence that a jury can use- relevance, unfair surprise, efficiency, reliability, and overall fairness of the adversary process. One rule that is particularly relevant to neurolaw is Rule 403. Rule 403 states that “the court may exclude relevant evidence if its probative value is substantially outweighed by a danger of one or more of the following: unfair prejudice, confusing the issues, misleading the jury, undue delay, wasting time, or needlessly presenting cumulative evidence”. This Rule is important to neurolaw as the people of the jury are laymen and usually do not have a background in neuroscience, and therefore can be swayed by concepts that they do not understand. Consequently, this type of evidence must be presented objectively and in a way that a jury can fully and completely understand, despite not knowing anything about neuroimaging.
Potential Use and Application
The many advancements in neuroscience also give way to many different categories of use for brain imaging within the legal system. Originally, brain imaging had mostly been used in medical cases for proving instances such as medical malpractice, but with the renewed abilities of brain imaging in conjunction with breakthroughs in neuroscience, brain imaging has become significantly more versatile as evidence.
One potential use of neuroimaging that is being researched is their ability to prove pain and suffering for civil litigations. Currently, “pain and suffering” is purely conceptual and relies on testimonial evidence to convince a jury or a judge of the damage done. If neuroimaging for this purpose is accepted as evidence, pain and suffering can become more obvious and concrete. As of now, those involved in court decisions have to decide for themselves whether or not a plaintiff is credible in canvassing their pain, which lacks a certain objectivity. In addition to other types of scans, such as CT and MRI scans, researchers are finding that fMRIs are particularly helpful for this purpose. While there are mixed opinions on whether or not fMRIs are reliable and accurate, there has been a significant amount of research improving their usefulness in recent years. In 2013, a study in which researchers developed an fMRI-based measure that predicts pain intensity individualized to the particular participant had promising results that it is possible to use fMRI to assess pain in healthy persons. As of now, the admissibility of fMRIs in civil litigations comes down to the credibility of the expert witness, but with the continued research in this field, it will become more universally accepted and therefore more universally admissible.
Another civil application of brain imaging is in matters regarding the elderly and their brain capacity and function. According to several European researchers, neuroimaging could be an important contribution to the field of neurolaw because it can detect brain aging and the various ways it affects cognition. This can be crucial for this demographic of people, as full control of cognitive and volitional functions is necessary to maintain a whole series of rights linked to legal capacity. In other words, neuroimaging might have a place in determining whether or not a person is competent enough to make decisions regarding their own life. Neuroscience has already shown us that juveniles have a reduced capacity to control impulses and understand consequences due to an underdeveloped frontal lobe, and it has already shown that it can show brain aging as well. While neuroscience for juveniles is already established in law (ie juveniles cannot recieve the death penalty due to reduced brain capacity), it is just now starting to be used for the elderly.
According to Nita Farahany, a legal scholar at Duke, approximately 2,800 criminal cases between 2000 and 2015 involved the use of neuroscience- which included anything from medical records to brain scans.
Arguments
As with any research advancement, there has been a lot of backlash against the use of brain imaging in legal proceedings. The most prominent argument is a typical one in the world of law- is using brain imaging infringing upon privacy and privacy rights?
Furthermore, many argue that attempting to use brain imaging as a mitigating factor in criminal cases is unjust. If a defendant has a brain abnormality, does that mean that they are not culpable for what they have done? In this case, the interpretation of the brain imaging is important. This is very similar to the argument used in conversation surrounding the insanity plea. In order to be able to say a defendant was “insane” at the time of the crime, typically the defense must prove that the defendant did not understand right from wrong or wasn’t able to act within legal constraints at the time of the crime due to a mental defect (each state has a different standard). It is still very possible to commit a heinous crime and not be “insane”, and it is also possible to be extremely mentally ill and still be aware of what is right and wrong. Mental illness does not automatically mean that a person is any less culpable of their crime. We can also apply this logic to criminal cases involving brain imaging. As with cases involving the insanity defense, any case must prove that a defendant had both elements of a crime- actus reus (guilty act) and mens rea (guilty mind). While it is possible that a brain abnormality can cause a person to act in a way that they usually wouldn’t or be incompetent in some capacity, this is not true of all abnormalities. Furthermore, brain imaging cannot show what was going on in a person’s brain specifically at the time of the crime, only at the time of the test. At the end of the day, the most important thing to look for is the intent to do harm and control over conduct. This kind of evidence does have the potential to do both harm and good, depending on how well it is presented and used. Juries must be instructed on the limitations of brain imaging and must have a full understanding of what the brain imaging shows in a way that they, as laymen, can understand. In addition, brain imaging should only be used to answer specific questions- it should not just be put out in a case, the relevance of it to the case and the questions at hand matters. Brain imaging must still be used cautiously and sparingly while brain imaging technology improves- we have impressive tools with incredible capacity, but they are still far from perfect.
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