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Great Expectations: The Effects of Neuroscience on the American Legal System

lrifkin's picture

Lea Rifkin
Biology 202
Professor Grobstein
Spring 2007
Web Paper 2

Great Expectations:
The Effects of Neuroscience on the American Legal System

Most Americans take comfort in the legal system that has been built to protect them. Law in America is generally believed to be stable, secure, and solid. It is a system which has been in existence since the birth of our country itself, and which has served American's well with little modification throughout the years. The legal system in the United States of America has survived cultural change, political turmoil, and scientific discovery in the past, and it will continue to do so in the future. Today, exciting advances in the field of Neuroscience provide new opportunities for the American legal system. However, with new opportunities come new challenges. Brain scan technology could eventually provide us with the ability to determine whether an individual is prone to commit a crime, whether a jury member is biased, whether a convicted murderer was able to make a rational decision, and whether or not an individual is lying. Yet, these possibilities also provoke moral questions as to what responsibility entails, what the domain of the legal system covers, and at what point we consider evidence valid, tested, and accurate.

In many ways, Neuroscience is a new frontier of the legal system in the United States of America. With the use of many Neuroscientific techniques, concepts, tools, and ideas comes the ability to come to conclusions that were never possible before. For example, brain scans are being combined with Implicit Association Tests, or I.A.T.s. This new combination test can be used to test biases, which can be useful when attempting to compile a jury. In preliminary studies, such tests have been used as individuals have been shown images of both black and white people while having their brains scanned. Functional Magnetic Resonance Imaging (f.M.R.I.) is also a relatively new technique with exciting possibilities. The f.M.R.I. technology allows Neurobiologists to see exactly what part of an individual's brain lights up when they partake in specific activities. Thus, although scientists are aware that specific areas of the brain handle specific types of action and information, this test allows them to see variation between individuals. The f.M.R.I. technology is also being used to develop new lie detectors. One of these new types of lie detectors compares the brain activity of liars with the brain activity of truth tellers. Another form of this new technology identifies when an individual recognizes an image, a smell, a person, a sound, or a crime scene that they are shown, versus when an individual is unfamiliar with what is presented to them. A third new development, known as positron-emission tomography, or PET scans, allow for participants to be injected with a solution that contains radioactive markers. These markers illuminate brain activity and allow Neuroscientists to identify damaged areas of the brain. These damaged areas may have caused an individual to have made a specific decisions or may explain why an individual reacted in a specific way. This new technology obviously has strong potential to both bring additional evidence into the court of law and to change the way the American legal system looks at evidence (1).

However, as many who work in both the fields of Neuroscience and the law have noted, it is important to cautiously and slowly analyze how this fusion, which has begun to be called “Neurolaw” will look (1). Along with the many benefits that Neuroscience has the potential to bring to the American justice system, there are challenges as well. The most widespread concern amongst professionals in the field is that the Neuroscientific techniques that are beginning to draw attention and appear attractive have actually not yet “gained general acceptance in the particular field [to] which [they] belong” (2). Although the United States Supreme Court has ruled that evidence should not be considered unless Judges have looked at “whether the underlying theory or technique is testable (and whether it has been tested), whether it has been subjected to peer review and publication, its known or potential error rate, and its general acceptance in the relevant scientific community” (2), even Neuroscientists involved in created in techniques which have the ability to effect the law are wary. In fact, The American Association for the Advancement of Science held an invitational meeting in 2004 to discuss “Neuroscience and the Law” (4). At this meeting, lawyers, Neuroscientists, judges, law professors, psychologists, and psychiatrists all agreed that:
“The use of flawed or incomplete science, or the reliance on scientific predictions beyond what the science is prepared to support, are exactly the kinds of concerns that should be foremost in the public mind when contemplating the potential social impact of predictive technologies or techniques” (4)

However, there are also more specific concerns within the field of Neurolaw. For example, even some of the scientists involved in developing the brain scan and I.A.T. combination tests explained that results cannot necessarily detect bias. They are more apt to notice whether or not participants have an awareness of “social reality,” or the disadvantage that certain groups face (1). Neuroscience based lie detection also brings difficult questions to the table. Currently, Neuroscience based lie detection is only as accurate as traditional lie detection techniques (1). However, even if Neuroscience based lie detection reaches a 100 percent accuracy rate, important legal issues will remain. These include freedom of thought under the Fifth Amendment and concerns over safety issues involved in these tests (4). Thus, unless courts found these tests to be inappropriately invasive, such as stomach pumps, would we force people to testify against themselves? Would the American legal system make lie detection tests mandatory (1)? Another popular use of Neuroscience in law is to determine what is different about a particular criminal's brain. However, as a culture Americans will need to make decisions regarding responsibility and choice. If a criminal had pressure on his or her amygdala or an abnormal cyst nestled in his arachnoid membrane does he or she abdicate all responsibility for his crime (1)? Although in the future Neuroscientists are looking at the possibility of memory downloading, or the ability to retrieve an individuals memory from their brain and store it in an alternative location, which presents numerous issues including whether or not police would need a warrant to search an individuals skull, presently technology is being developed which focuses on predicting the future. This technology aims to predict whether an individual is prone to violence or criminal action and must be utilized with extreme caution (1) as “it is near the core of our justice system that we reward people, punish them, or hold them responsible for their actions, not their thoughts (or potential actions)” (4). If at all flawed, this technology could also lead to the punishment of many innocent individuals.

The possibilities that Neuroscientific discovery provide for the American legal system are ever expanding, inspiring, and thought provoking. While Neuroscience does have the potential to revolutionize the justice system in the United States, more proof must be provided before lives are put at stake. Although brain imaging results have already been utilized in the court of law (3), it has been argued that Neuroscience has less potential to revolutionize the legal system than it does to change the way the public views criminal activity, responsibility, free will, and choice (5). However, as has already been shown, Neuroscience will play a role in American law. Thus, techniques must be further developed and refined, which time will allow for. It is also important that both scientists and those involved in the legal system cautiously analyze both the methods used and the outcomes such methods will provide. Until new Neuroscientific measures can be proven, they cannot be trusted in the court of law. Only time will tell whether our faith and excitement in “Neurolaw” will show fruitful results, or prove to have been just a great expectation?



Rosen, J. (2007, March 11). The brain on the stand. The New
York Times Magazine, Section 6. 48-53, 48-53,
70, 77, 82-83.






Tom Wilson's picture

lie detection

In any discussion of fMRI lie detection I think two thing are reasonable to include in the discussion. First, that a new level of admisiblity not be set for this technology than for other technology that is currently admitted in court unless specific proof to do so can be brought forward. Secondly, I think new technolgy should be viewed in relation to current error rates of court outcomes. If we simply look at the advent of DNA testing and those proven to be wrongfully convicted it should be sobering. DNA evidence is only relevant in a very small number of court cases. If we extrapolate from that there are probablly thousands or tens of thousands of wrongful convictions - let alone those wrongfully aquitted. The test for new types of evidence should not be that it is 100%, but rather is it better than what we are doing now while we work at making it even better.