My brain made me do it – a problematic schism between neuroscience and the law | Legal Aware
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There is no doubt that a number of factors potentially lead in increased levels of crime in society, for examples gang culture, or population density. This requires a different experimental approach altogether to considering how the legal and neuroscientific approaches can be made to converge in the “mens rea” of the crime, which we have previously discussed elsewhere.
The degree to which a person can be truly culpable of crime is to do with the degree of his voluntariness. That is when the factors which are ‘internal’ to someone can be highly relevant. For example, in one isolated study, significantly higher testosterone levels were found among violent female outpatients than among the non-violent ones, whose levels were similar to those reported for normal females. This study reported increased irritability among violent patients during menstruation, which is consistent with other research showing associations between criminality and both premenstrual and menstrual periods (1). Obviously, as a society, some people perhaps believe that, culturally, women cannot blame their periods for a crime. Criminal law,cthrough a combination of case-made law and statute law,chas stumbled its way through dealing with mental illness in the US and UK jurisdictions.The discussion here centres on the English jurisdiction, except where stated otherwise.
The evolution of this law has been almost exactly, punctuated at various intervals with observations from the law, rarely neuroscience, cognitive neurology and neuropsychiatry, being put on a statutory footing. The best paradigm of the interface and the law is arguable the defence is the insanity defence. Embarrassingly, this defence has its roots in a very old case in English law. In 1800 James Hadfield was found to be insane on a charge of the attempted murder of George III (2), but he received an outright acquittal. Public and political reaction to this case led in turn to the enactment of the Criminal Lunatics Act 1800 which required the courts to order anyone who had been acquitted by reason of insanity of various serious offences to be detained until His (or Her) Majesty’s pleasure be known. The rules which provide for the insanity defence to be satisfied are known as the “McNaghten Rules” (1842) (3). Firstly, all defendants are presumed sane. On a balance of probabilities, the defendant must prove that at the time the offence, he was labouring under such a defect of reason, arising from a disease of the mind, and that he did not to know the nature and quality of the act he was doing, or, if he did know. it that he did not know that what he was doing was wrong. The jury can therefore return a special verdict of ”not guilty by reason of insanity”. Before the 1957 Act, over 40% of murder trials involved a plea of insanity. Now most defendants will opt of the defence of diminished responsibility. Insanity is a rare defence compared to diminished responsibility.
The law on diminished responsibility is contained in s.2 Homicide Act [1957], and has the following definition:
2 Persons suffering from diminished responsibility
(1)Where a person kills or is a party to the killing of another, he shall not be convicted of murder if he was suffering from such abnormality of mind (whether arising from a condition of arrested or retarded development of mind or any inherent causes or induced by disease or injury) as substantially impaired his mental responsibility for his acts and omissions in doing or being a party to the killing.
(2)On a charge of murder, it shall be for the defence to prove that the person charged is by virtue of this section not liable to be convicted of murder.
(3)A person who but for this section would be liable, whether as principal or as accessory, to be convicted of murder shall be liable instead to be convicted of manslaughter.
(4)The fact that one party to a killing is by virtue of this section not liable to be convicted of murder shall not affect the question whether the killing amounted to murder in the case of any other party to it.
In Byrne [1960] Lord Parker defined ‘abnormality of mind’ as: “a state of mind so different from that of ordinary human beings that the reasonable man would term it abnormal. It appears to us to be wide enough to cover the mind’s activities in all its aspects, not only the perception of physical acts and matters, and the ability to form a rational judgment as to whether an act is right or wrong, but also the ability to exercise willpower to control physical acts in accordance with that rational judgment.” (4) Byrne was a sexual psychopath who found it difficult, if not impossible, to control his perverted sexual desires he strangled a young woman and horrifyingly mutilated the body.
However, the key concept of “disease of the mind” has no agreed psychiatric meaning. As interpreted by the courts, it has even come to include conditions that are not mental disorders, such as epilepsy and diabetes, The Law Commission in their introduction to their consultation on “Unfitness to plead and the Insanity defense”, provide that, “Given the vulnerability of the mentally ill and the increasing frequency with which they are coming into contact with the criminal justice system, modern criminal law should be informed by modern science, and in particular by modern psychiatric thinking.” (5) There is no doubt at all that at the time the rules over insanity and diminished responsibility were formulated, cognitive neuroscience was its infancy.
The application of these antiquated rules has become felt by may as being increasingly difficult, problematic, and artificial. One of the most rapidly advancing fields is neurogenetics. This should be to both cognitive neuroscientists and experts in jurisprudence. Criminal defendants most often offer behavioral predispositions as evidence to mitigate punishment after a finding of guilt, rather than as a defense to criminal liability (People v Sapp [2003]) (6)
Denno (1988) argues that,
“no strong evidence supports either a strictly free will or a strictly deterministic philosophy in the criminal law regarding either the causes of crime or the determinants of criminal responsibility.”
Denno further emphasizes the need that the criminal justice system must evaluate the neuroscience of this behaviour with a view to constructing sensible policy (7). A now historic case (People v Tanner [1970] (8)) failed prove innocent a defendant, with an extra Y chromosome, guilty of kidnapping, forcible rape, and assault with intent to commit murder, was found to have an extra Y chromosome. The two expert witnesses, who were geneticists, stated that their research and that of others demonstrated a causal link between the XYY chromosome disorder and aggressive behaviour.
However, leading academics Farahany and Coleman (2006) describe graphically the double-edged sword of arguing a genetic predisposition for criminal behaviour, by providing that, “Not only have criminal defendants experienced little success by introducing behavioral genetics during sentencing; in some cases it has cut against the defendant, courts have regarded the genetic predisposition of defendants as a potential aggravating sentencing factor or circumstance.” (9) In a final blog tomorrow in this series of articles, we consider the neurological evidence regarding free will from the alien hand syndrome and Gilles de la Tourette syndrome.
References
(1) Ehlers, Rickler & Hovey, A Possible Relationship Between Plasma Testosterone and Aggressive Behavior in a Female Outpatient Population, in Limbic Epilepsy and the Dyscontrol Syndrome 183, 191 (M. Girgis & L. Kiloh eds. 1980).
(2) Hadfield (1800) 27. St Tr 1281
(3) McNaghten (1843) 8 ER 718
(4) R v Byrne B [1960] 44 Cr App R 246; [1960] 2 QB 396
(5) http://www.lawcom.gov.uk/insanity.htm accessed 26.2.10
(6) People v. Sapp, 73 P.3d 433, 469–73 (Cal. 2003) (introducing the defendant’s psychological and neurological factors contributing to the homicide as mitigating evidence).
(7) Denno, DW. Human biology and criminal responsibility: free will or free ride? University of Pennyslvania Law Review (1988) 137: 651-671.
(8) 3 Cal.App.3d 596, 91 Cal.Rptr. 656, 42 ALR3d 1408 (1970
(9) Farahany, NA, Coleman, J. Genetics and responsibility: to know the criminal from the crime. Law and Contemporary Problems Vol. 69, p. 115, June 2006, Vanderbilt Public Law Research Paper No. 06-14, Duke Law School Legal Studies Paper No. 110
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