Neuroscience is the study of the nervous system for understanding how the brain regulates the body and behavior of an individual giving rise to his/her consciousness. This has immensely contributed in the prevention and cure of neurological and psychiatric disorders.

Our criminal justice system has been encouraging the admission of new types of evidences which are the upshots of the latest scientific and technological developments.

One of these newly admitted evidences is the neuroscientific evidence which has created serious controversies as it is relatively new and inexperienced. This tool can be used by the defense attorneys to reduce or even exculpate the criminal responsibility of their clients.

This article analyses how conscious will of an individual is related to freedom and responsibility while committing a crime and how this tool proves effective in establishing and sometimes reducing the guilt of an offender. The article focuses on the types of neuroscientific evidences and when they become material [i]under the recognized legal parameters for examining criminal liability and punishments. The article also focuses on the obstacles to the presentation of this evidence at both trial and sentencing.

Science And Law: a brief history

Science in all forms has in recent times invaded the courtroom symposium whether it is DNA testing, chemical tests, brain imaging and lie detection techniques, psychiatric tests etc. The desire to use science in courtroom among the attorneys has increased exponentially over the years. Science and law have always exhibited love- hate relationship. The love part commences from the fact that science helps in reducing the complexities of the law by providing greater amount of certainty.

The hate part on the other hand emanates from the fact that science used by the lawyers who are not well equipped in this field often leads to unreliability. From the advent of Electro-encephalography (EEG) in 1930s to the Magnetic Resonance Imaging (MRI) scans performed in 1970s, the discipline of neuroscience has observed notable evolution.

In 1940, EEG was used for the first time in a case of a defendant suffering from epilepsy. EEG measures various activities of the brain by placing electrodes on various portions of head and [1]then recording various electrical impulses emanating in the nerve cells present in the outer region of the brain. After few years again in 1981, Computed Tomography was introduced to scan the brain of John Hickley who was charged with attempt to murder of President Ronald Raegan.

He was alleged to have been suffering from Schizophrenia. The indifference of the legal system towards such incapacitated persons was debated by the defense counsel. The judges of the district court admitted this evidence in order to ensure maximum authenticity and subsequently found him not guilty by the reason of insanity.

The data in the table above illuminates the fact that admissibility of neuroscientific evidence has significantly elevated in recent years across various countries with the U.S.A at the top of the list. However, there has been great variation across different legal systems in deciding upon the admissibility of this type of evidence in courtrooms and its impact on juristic decisions, for instance it has led to decrease in detention time in the U.S.A in contrast to that in Germany. Also, the intersection between the neuroscience and law is crucial in order to reflect the use of these techniques for diagnosis, risk assessment and treatment.

Admissibility Of Neuroscientific Evidences In Courts

Albeit, there has been significant increase in the inclination of the judges towards the admissibility of this evidence, the neuroscientific evidence can have mitigating effect only under some circumstances in criminal adjudication especially at sentencing.

In order to make the evidences admissible into the courts, how the attorneys should frame the claims and make them germane to the criminal law doctrines is the question. The admissibility of the neuroscientific evidence depends on the five types of neuroscience evidences. The first two are weakly material at the trial while the last three are more likely to be relevant both at trial and sentencing.

1. Evidence of abnormality- evidence showing that defendant is suffering from a neurological impairment e.g. Frontal Lobe Disorder (FLD). The brain scan of the defendant done by using MRI technique can show that his frontal lobe area of the brain ( associated with planning and decision making) and the left side of the limbic system (associated with regulation of emotions) exhibits reduction in volume.
   
   It may seem on the very face that such evidences are highly material; however the courts are reluctant to admit these evidences most of the times. In a famous case, a Virginia school teacher at the age of 37 suddenly developed interest in child pornography and sexually propositioned his step daughter. It was found that he had developed brain tumor and after the surgery his sexually motivated conduct dwindled.
   
   A case like this which establishes lucid and direct causative link between the neurological defect and the crime is very unusual. In majority of the cases this evidence fails to establish the causative link between the abnormality and the crime; also it is very difficult to ascertain the presence of the abnormality during the time of commission of the crime and its significant contribution in the crime. This evidence is rarely pertinent at trial and sentencing.
    
2. Cause of effect evidence- this evidence tends to show that many people with neurological impairment exhibit antisocial behavior i.e. most of the criminals have FLD. It makes an earnest attempt to establish the fact that it was not the offender but his brain which occasioned him to commit the crime. But again this category of neurological evidence is no better than the abnormality evidence as it too fails to provide as to how the [2]abnormality contributed to the commission of the crime, which is the central question the law postulates to be answered.
    
3. Effect of cause evidence- this evidence endeavors to show that violent behavior is the effect of the neurological impairment i.e. people with FLD are more likely to commit crimes. This category to some extent succeeds in establishing the causative link between the violent behavior and neurological impairment by comparing the prevalence of iniquitous behavior among those with some neurological impairment to those lacking any of such impairment. For instance, in a study it is found that the prevalence of vicious behavior in persons with neurological defect is 10% higher than in persons lacking such impairment; the data suggest that neurological impairment predisposes people to commit crime.
   
   However, the critics argue that there is some or the other cause behind each crime, if the juries will begin to mitigate or exculpate the punishment on the basis of these causes then every criminal will try to manipulate the law in his favour. In some cases where the defense attorney presents strong evidence that the criminal behavior was the cause of neurological impairment, the prosecution will try to point out the planning component of the crime, which will extirpate the volitional impairment claim. The prosecutions can also emphasis the fact that many people with these impairments do not commit such crimes thus proving that control is possible. In short, the attorneys need to be meticulous as though this category is better than the first two; it comes with its own impediments.
    
4. Impairments that are legally relevant- this type of evidence entails the process behavioral study and gauging of the defendants ability to control, plan, form intentions and various other germane enquiries made by the neurologists. This differs from the simple evidence of abnormality as it provides an insight into the defendant’s functioning. However, the degree of impulsivity differs at different point of time and situations. It cannot be said with certainty that the defendant shows same impulsivity at the time of committing the crime.
    
5. Impairments that law recognizes to be exculpatory- this is based on the doctrine of “scientific stare decisis” which was laid down in the case of Sears Vs Upton. According to this doctrine, if a 30 year old man’s and a juvenile’s brain functions alike then the court shall evaluate their culpability in the same manner. Synonymously, the criminality is more proximately linked to the maturity of the brain than to the age of the person. However, the attorneys should punctiliously frame this neuroscientific evidence as this evidence may indicate high recidivism risk.

The admissibility of neuroscience in order to evade criminal responsibility is tremendously dependent upon the defensive arguments formulated by the defense attorneys. There are four plausible arguments which can prove to be highly germane by the judges. First one being the claim that defendant’s act was involuntary. This requires the proof of lack of conscious control over the body as in the case of sleepwalking or epilepsy.

A murderer shall not be responsible for the killing if he has not acted from free will. Freedom and responsibility of a criminal act entails more than just intention and will to do the act. Some legal jurisdictions explicitly mandates conscious will as elements of crime.

For example a friend cooks soup with peanuts for a friend who is allergic to peanuts. The cook was not negligent and his conscious goal was to make the friend happy. The prosecutor’s argument that the cook had some unconscious will to harm his friend will not hold him responsible as he had no conscious control over such unconscious will. The antithetical view is that there is always some connection between the brain and behavior.

This claim is rarely befitted in the courts in determining criminal responsibility. The famous “sleep walking case” in 1981 which drew much publicity in Arizona, in which the defendant was charged with killing his wife with a kitchen knife by stabbing her 26 times. He claimed that he did not remember anything as he was sleeping at that time. The jury found him not guilty on the ground lack of consciousness during the commission of the crime.

The second legal defense tends to focus on the “mens rea” element of the crime which is indispensable in establishing the criminal responsibility. This requirement may vary between different jurisdictions over time. The intention element is followed by the preparation and then the actus reus component of the body of the crime. It is defined as [3]commitment to a plan of action. For the act to be intentional, the actor must know that he is planning and performing the act. For establishing mens rea the prosecution needs to show that the offender had relevant designs to accomplish his motive.

However, the defense attorney can show through various brain imaging techniques that the defendant’s brain has certain functional impairments due to which it is not possible for the defendant to form and commit to plans of action. If these defense arguments prevail, the criminal responsibility diminishes to a great extent. The famous case of Andrea Yates, the women who drowned her five children in the bath tub in 2001. She had been suffering from a very severe postpartum depression and schizophrenia. She was not found guilty by the courts by reason of her mental incapacity.

The third possible legal defense is associated with insanity. The earliest case on this matter is that of R. Vs Arnold in 1724 decided by the English court. He was acquitted by the jury pointing him out to be a madman who is exempted from punishment and that he was no more than an infant and such a man should never be an object of punishment.

In the famous case of Daniel M’Naghten in 1840, from which the famous M’Naghten rule was derived; Daniel M’Naghten who was charged with murder of Sir Robert Peel, the private secretary of the then Prime Minister of England, was acquitted on the ground of insanity.

Their lordship observed that every man is presumed to be sane to be held responsible for his crime until contrary is proved. In order to establish this defense it must be clearly proved that at the time of committing the offense the accused was incapable of understanding both the nature and the consequences of the said act by the reason of mental impairment.

However, such mental and volitional impairment should be a serious one to be recognized by the jury as a defense. If a little knowledge about the consequences and the nature of the criminal act is proved by the prosecution, this defensive argument fails.

Conclusion
As stated above, use of neuroscience evidences in courtroom symposium has increased tremendously, but with this blooming advancement lays various queries which need to be addressed. The language of law and the language of neuroscience are stupendously different. The experts of both fields must together develop a set of rules in order to gauge when a particular defendant’s neurological profile conforms to the legal requirements. These rules must be prudently examined as they being too liberal will set free the guilty and they being too strict will make the innocent to suffer.

As this field is new and inexperienced, Neurolaw scholarship among the lawyers and juries should be ameliorated by spending more time with the experts of this field wrestling with the types of evidence useful in the courts. Experts should be appointed to explain these evidences to the juries who are naïve in this field. This is crucial because the responsibility to examine the facts and to devise any judgment based on these facts is upon the judges hence the judgment should not be an erroneous one.

The double-edged sword dilemma which is characterized as indicative of high risks must also be addressed. The neurological evidence is often exploited by the prosecution when it indicated that the offender poses high future risks to the general public.

But anecdotally, the defense attorneys are clearly concerned about this fact. However with all these issues and challenges, neuroscience can be helpful in reforming the present retributively driven system, by both preventing as well as rehabilitating the offender. Neuroscience experts would focus on risks and treatment thus uprooting the cause behind such antisocial behavior.

1. Christopher Slobogin, “Neuroscience nuance: dissecting the relevance of neuroscience in adjudicating criminal culpability.” Journal of law and Biosciences, 577-593 (2017).
2. Deborah W. Denno, “The Myth of the Double-Edged Sword: An Empirical Study of Neuroscience Evidence in Criminal Cases” Boston college law review, Volume 56, Issue 2, Article 3 (2015).
3. U.S. v. Hinckley, 525F.Supp. 1342 [D.D.C. 1981].
4. Eyal Aharoni, Chadd Funk, Walter Sinnott-Armstrongand Michael Gazzaniga, “Can Neurological Evidence Help Courts Assess Criminal Responsibility? Lessons from Law and Neuroscience, University of California.
5. Paul Catley and Lisa Claydon, “The use of neuroscientific evidence in the courtroom by those accused of criminal offenses in England and Wales.” Journal of Law and the Biosciences, 510–549, Advance Access Publication [14 July 2015].
6. Andrea L. Glenn, Adrian Raine, “Neurocriminology: Implications for the Punishment, Prediction and Prevention of Criminal Behaviour” Neuroethics Publications,[2014].
7. Rex vs. Arnold (1724).
8. R v M'Naghten (1843) 8 E.R. 718; (1843) 10 Cl. & F. 200.
9. The Honorable Jed S. Rakoff, “ Science and the Law: Uncomfortable Bedfellows” [2008].
10. Francis X. Shen, “Neuroscientific evidence as instance replay” Journal of law and the Biosciences, volume3 issue 2, 343-349 (2016).