Abstract
Recently the role of neuroscience in assessing criminal responsibility has become an issue of academic and practical debate. The question that arises is the role that neurological or brain disorders can play in assessing criminal responsibility. Within the context of South African criminal law, the question arises as to whether these disorders will meet the threshold requirements for the defence of pathological criminal incapacity. Various medico-legal issues arise when assessing the role of neurological disorders in relation to criminal responsibility. In this contribution, the reflections are provided pertaining to the role of neuroscientific evidence in explaining criminal responsibility within the context of selected areas of application. Evidentiary aspects pertaining to the presentation of neuroscientific evidence are further canvassed as well as the role of neuroscientific evidence advanced in support of mitigation of punishment.
Keywords: criminal capacity, diminished responsibility, expert evidence, insanity, neuroscience, South African law
(Neuroscience) is one of those things that holds both promise and terror for the legal system 1
1. Introduction
Shortly after his fortieth birthday, Michael suddenly developed a fascination and interest in child pornography, despite never having had any interest in such materials up to that point in his life. In addition, Michael found himself attracted to his 12-year-old stepdaughter who stayed with him and his wife. One night, after putting his stepdaughter to bed, he sexually molested her. Michael was consequently convicted of sexual molestation of a child.2 Michael was granted the option of attending a treatment programme in order not to receive a prison sentence. He attended the programme but performed poorly and also made sexual advances towards members of staff and other patients.3
Michael started complaining of headaches, and it was recommended by a neurologist that he undergo a structural magnetic-resonance imaging (MRI) of his brain. The MRI revealed a large orbital-frontal tumour. Michael had to undergo surgery to remove the tumour. After surgery, his sexual urges in respect of children ceased. Michael returned to the treatment programme and passed without any obstacles. Several months later, Michael’s sexual desires for children returned. A further MRI revealed that the tumour had returned. After undergoing further surgery, the tumour was again removed, and once again Michael’s urges ceased.4
The facts above serve to set the stage for the discussion dealing with the role of neuroscience in explaining criminal behaviour. Michael’s case, as unique as the facts were, provides an illustration of an alternative explanation in respect of the possible cause of his criminal behaviour, ultimately taking a different slant as opposed to the classic forensic psychiatric model in terms of assessing for mental illness, specifically in cases where mental illness giving rise to the insanity defence is claimed. Recently, neuroscientific research is becoming increasingly useful in advancing our understanding of the neural correlates of human behaviour, cognition and emotion and could potentially become highly significant when criminal responsibility falls to be assessed.5
One of the primary fields where neuroscience could find application is in respect of criminal responsibility. There are principally three areas of brain abnormalities that are of significance for the purposes of assessing criminal responsibility: impairments of the frontal lobes; abnormalities in the limbic system, with associated problems in affective processing and potential adverse effects of neurotechnologies control.6 The advances within the field of neuroscience raise fundamental questions which could be of relevance also within South African law. The interaction between neuroscience and law has, in addition, been coined ‘neurolaw’, which classically deals with the interplay between the legal system and advances made within the field of neuroscience.7 In this contribution, the emerging nature of neuroscience will be addressed within the context of South African criminal law with specific reference to its applicability to different levels of criminal liability.
2. The emerging nature and ambit of modern neuroscience
The intersections between modern neuroscience and the law can generally be divided into three subsections – the law of neuroscience; neuroscience and the law and neuroscience in law. The first level refers to the regulation of neuroscientific research with an emphasis on aspects such as informed consent and also research involving human participants.8 The second level of neurolaw refers to the neuroscience relating to normative judgment and decision-making.9
The third level that is topical for the purposes of the current discussion refers to the study of cognition and behavioural patterns relevant for legal purposes, which include impulse control, moral reasoning, and psychopathy as well as drug addiction.10 As such, one of the primary fields of the applications of neuroscience within the context of the third category refers to the possibility of assessing criminal responsibility.11 The question that arises in respect of the role of neuroscience in assessing criminal responsibility is the following: if neuroscientific research indicates abnormal brain functioning of an accused in terms of, for example, lacking impulse control, whether such accused can be held criminally responsible for his or her acts. Klaming and Koops note that neuroscientific evidence has been used in various cases to argue for diminished criminal responsibility, such as in the Netherlands.12 Shen, in addition, states that neuroscience has been used by the courts in the following ways:13
brain data have been utilised to indicate personality changes after head trauma;
brain scans have been used to assess competency to stand trial;
brain scans have been used in mitigation of sentence where there is evidence of brain trauma;
brain scans have been used in cases involving sexual offences; and
neuroimaging evidence has been used in support of insanity cases.
From the outset it is important to note that neuroscientific evidence can be employed by both prosecution and defence in a criminal trial. For example, neuroscience can be used to shed light on potential future dangerousness of an accused.14
Gazzaniga defines cognitive neuroscience as ‘the field of scientific endeavour that is trying to understand how the brain enables the mind’.15 Page notes that advancements in respect of brain imaging provide objective, reliable information about the structural and functional aspects of the brain, which may assist judges in comprehending an offender’s state of mind.16 As such, cognitive neuroscience can potentially address two aspects of criminal responsibility, namely intention and insanity.17 Neuroscience essentially deals with the human brain and seeks to enhance the understanding of how human behaviour and, as such, also criminal behaviour is influenced by the brain. Compton notes the following in respect of neurological research:18
If researchers can use neuroimages to show a direct relationship between the brain and mental and behavioural processes, neuroscience could impact the legal analysis of personal responsibility for past actions, assessment of a person’s existing state of mind, and prediction of future behaviour.
Neuroscience provides interesting possibilities of science being able to reveal the intricate workings of a person’s mind.19 Compton correctly cautions that the brain is a highly complex system, and science has only begun to comprehend the structure and functioning of the brain and the ultimate effect on behavioural processes.20 Neuroscientific evidence generally requires neuroimaging which entails computer-generated images of the brain and is utilised to describe both structural and functional images.21 Experts will essentially employ computed tomography (CT) scanning and magnetic resonance imaging (MRI).22 These techniques can typically expose physical abnormalities caused by trauma or brain disease and are often supported for their use as evidence as they depict the physical observable structures of the brain.23 More recent forms of neuroimaging with reference to the functional MRI (fMRI) measure the functioning of the brain by locating active brain areas by measuring the blood flow to a particular section of the brain.24 The CT and MRI scans depict a black-and-white picture of the brain structure, whereas the fMRI scans indicate localised changes in blood flow.25 The latter is then displayed on a three-dimensional computer-generated image of the brain to provide a comprehensive exposition of the functioning and structure of the brain.26 Due to the novel nature of fMRI technology, CT and MRI images are mainly or primarily utilised to indicate structural abnormalities of the brain itself.27 Research indicates that neuroscience evidence has been admitted in criminal trials mainly for purposes of sentencing but has recently made strides during the assessment of guilt for purposes of establishing criminal responsibility as well.28 The use of neuroscientific evidence in criminal trials, more specifically in terms of assessing criminal responsibility, raises concerns relating to its scientific reliability and validity. It could be argued that this evidence should nevertheless be admitted in conjunction with forensic psychiatric and psychological evidence to best portray an accused’s mental structure.29
3. Neuroscience and criminal responsibility: selected areas of application
With the emergence of neuroscientific research, the question that arises is within which domains the evidence can become relevant for purposes of assessing criminal responsibility. Klaming and Koops indicate that research on criminal responsibility has indicated a link between frontal lobe dysfunction and criminal behaviour as well as limbic dysfunction and criminal behaviour.30 Research indicates that damage to either of the latter brain regions could indicate pathologically disturbed mental capacities potentially resulting in a finding of diminished responsibility or even non-responsibility.31 For the purposes of the present discussion, emphasis will be placed on these two dysfunctions as examples of where neuroscience could find application with reference to criminal responsibility.
3.1. Frontal lobe dysfunction and criminal behaviour
While nothing is easier than to denounce the evil doer, nothing is more difficult than to understand him.32
Frontal lobe brain dysfunction has long been identified as a potential causal factor in violent crimes.33 Redding notes that neuropsychological research indicates that the prevalence of brain dysfunction among criminal populations is very high, with the highest correlation of 94% among homicide offenders, 61% in respect of habitually aggressive adult offenders, 49%–78% in respect of sex offenders and 76% among juvenile offenders.34 Research indicates that murderers generally have lower glucose metabolism in the prefrontal cortex which in turn indicates that prefrontal deficits in antisocial individuals could potentially predispose them to higher impulsivity and inhibited self-control.35 Dysfunctions in the frontal cortex can impact on an individual’s ability to control impulses and deliberate as to the consequences of their behaviour. Damage to the frontal lobes can be caused by mild or traumatic brain injuries or a brain tumour.36 A typical example of the latter would be the factual scenario depicted at the beginning of this article. Redding postulates that frontal lobe brain damage can result in changes in personality, mood and behaviour, ultimately resulting in ‘frontal lobe dysfunction’ or ‘frontal lobe syndrome’ and typical symptoms associated with frontal lobe disorder including:37
defects in goal determination;
defects in planning behaviour;
violent behaviour as a result of flat affect;
low frustration tolerance;
impaired self-control;
low conformance with societal values; and
sexual disinhibition.
Research indicates that brain imaging studies have pertinently revealed structural and functional abnormalities in the frontal lobes of violent and psychopathic individuals.38 Frontal lobe dysfunction is typified by at least two distinct forms, namely damage to the ventromedial prefrontal cortex, which is responsible for impulsive behaviour and aggression; and damage to the dorsolateral prefrontal cortex, resulting in impaired judgment and moral deliberation.39 Redding notes that numerous symptoms of Antisocial Personality Disorder are consistent with the symptoms of frontal lobe dysfunction.40 Similarly, the development of psychopathy may in selected cases be traced to frontal lobe damage early in life.41 It is also notable that the frontal lobes contain the brain’s primary serotonergic projections and, as such, abnormalities in serotonin metabolism may lead to impulsive aggression.42
3.2. Limbic system dysfunction and criminal behaviour
Research on psychopathy strongly suggests that psychopathic individuals have decreased activity in the limbic system, a structure situated in the middle of the brain which includes the hippocampus, hypothalamus and amygdala; as such, the limbic system is involved in various functions including the regulation of emotion.43 As a result of neurological research, some researchers believe that psychopathy is as much a mental illness as any other mental illness.44 Raine, for instance, has stated:45
Brain imaging research on violence and psychopathy is troubling to some because it challenges the way we conceptualize crime. It questions our treatment of violent [criminals] in just the same way that we now look back 200 years and question the way in which the mentally ill were kept in shackles and chains, treated little better than animals. The history of civilization has shown that as time progresses, society becomes more ennobled, wiser and humane. In 200 years from now, will we have reconceptualised … serious criminal behaviour as a clinical disorder with its roots in early social, biological, and genetic forces beyond the individual’s control?
4. Pathological criminal incapacity within the context of neuroscience
It is from the outset important to provide a brief prelude to the definition of the defence of pathological criminal incapacity as it currently operates within South African criminal law. Within the South African context, the defence of pathological criminal incapacity is embodied and as such defined in s 78(1) of the Criminal Procedure Act 51 of 1977 (‘the Act’).46 Section 78(1) provides that an accused is not criminally responsible for an act of omission which constitutes an offence if, at the time of the commission of the alleged offence, the accused suffered from a mental illness or mental defect which rendered him or her incapable of appreciating the wrongfulness of his or her act; or of acting in accordance with an appreciation of the wrongfulness of his or her act.47 According to Snyman, the test for pathological criminal incapacity comprises a pathological or biological leg which entails that the accused should have suffered from a mental illness or mental defect at the time of commission of the offence; and a psychological leg which entails that the accused should have, as a result of a mental illness or mental defect, lacked the capacity of appreciating the wrongfulness of the act or of acting in accordance with such appreciation.48 The test applied is accordingly a so-called ‘mixed’ test in that both the pathological as well as the psychological factors are taken into account in determining whether an accused lacked criminal capacity.49
The threshold requirement for the defence of pathological criminal incapacity is the existence of a mental illness or mental defect at the time of the commission of the act. This requirement is also referred to as the pathological leg of the test for criminal responsibility. The particular mental illness or mental defect must in addition render the accused incapable of appreciating the wrongfulness of his or her act, or acting in accordance with an appreciation of the wrongfulness of the act.50 The latter two defences apply in the alternative. Snyman, as well as Burchell and Milton, opine that ‘wrongfulness’ for purposes of the appreciation of the wrongfulness of an act should denote either legal wrongfulness or moral wrongfulness.51
In respect of the defence of pathological criminal incapacity, it is important to note that certain mental illnesses may not necessarily affect an accused’s capacity to appreciate the wrongfulness of his or her action, but may nevertheless deprive the accused of the ability to control their conduct or to act in accordance with the appreciation of wrongfulness.52
The test for pathological criminal incapacity or insanity does not define the terms ‘mental illness’ or ‘mental defect’ nor does it specify the particular mental disorders that constitute ‘mental illness’ or ‘mental defect’. What becomes evident is that the test only identifies the effects which should result from a particular ‘mental illness’ or ‘mental defect’. The pivotal role of the mental health professional in the definition and assessment of the mental illness becomes evident. A question that frequently arises is whether the definition of mental illness should be a medical or a legal prerogative. Slovenko pertinently encapsulates the dilemma as follows:
During the past two centuries the courts have often said that the term ‘disease of the mind’ or ‘mental disease or defect’ in the test of criminal responsibility is not a medical but a legal term. At the same time, however, since medical or psychiatric opinion is necessary to give meaning to the term, it becomes a fusion of legal and medical components. To be sure, no rule of law can be reliable when absolutely dependent on another discipline, but without input from other areas, the law would just be amid verbal agonizing.53
In respect of expert evidence by mental health professionals, a court is obliged in terms of s 78(2) of the Act to refer an accused for observation if it is alleged in criminal proceedings that an accused is by reason of mental illness or mental defect not criminally responsible or if it appears to the court that an accused is for such a reason not criminally responsible. The matter is then enquired into and reported on in accordance with s 79 of the Act, which provides for the panel of experts who are required to conduct the assessment and comply with the procedural aspects associated therewith.
Constructing a defence of pathological criminal incapacity due to a neurological dysfunction or disorder will accordingly entail firstly establishing a particular neurological disorder or brain dysfunction as a mental illness or mental defect for the purposes of s 78(1) as a threshold requirement. It will then have to be established that such a neurological disorder resulted either in the inability of the accused to appreciate the wrongfulness of his or her actions (cognitive capacity) or the inability to act in accordance with the appreciation of wrongfulness (conative capacity). If the cognitive or conative capacity of the accused was sufficiently impaired as a result of the brain dysfunction or neurological disorder, the accused is said to have lacked criminal capacity.
Within the context of neuroscience and the role of neurological disorders in assessing criminal responsibility, various questions arise. As was gleaned from the discussion above, the defence of pathological criminal incapacity deals essentially with ‘mental illness’ and/or ‘mental defect’. The question that inevitably arises is whether a neurological disorder will qualify as a ‘mental illness’ or ‘mental defect’ for the purposes of the defence of pathological criminal incapacity. A further related issue pertains to the situation similar to the factual scenario illustrated at the outset of this contribution. The example of Michael illustrates the scenario where an accused is only temporarily incapacitated due to a brain disorder or neurological disorder. Once such a disorder has resolved, the accused will no longer suffer from the disorder, in which event the defence of pathological criminal incapacity will no longer be feasible. In cases of frontal lobe disorder, it could be argued that the conative leg of the capacity test was absent. But once again one is brought back to the question as to whether this will be encompassed by the definition of mental illness or mental defect. To date no such cases have featured in South African criminal law. In addition, there have been no cases where the role of neuroscience in respect of criminal responsibility has been addressed. A further question that arises is what role neuroscience could play in respect of impulse control disorders that arise as a result of a brain dysfunction. Neurological disorders will undoubtedly influence an accused’s criminal capacity, but in most cases probably not to the extent of satisfying the insanity criteria. It could be argued that diminished criminal capacity would be a sound alternative in terms of dealing with brain disorders. However, the latter does not detract from the pivotal influence and role that neuroscience evidence can play in these cases, ultimately providing the court with a holistic view of the accused’s state at the time of the offence.
5. Admissibility of neuroscientific evidence
In order to comprehend the role of neuroscientific evidence within the paradigm of South African criminal law, an understanding of the basic and foundational principles of expert evidence within the South African context becomes essential. Expert evidence represents one of the exceptions to the general rule against opinion evidence.54 As such, the evidence presented by neuroscience experts will be meaningless to the criminal justice system if it is not relevant to the issues before the court.55 The opinion evidence of an expert will be deemed admissible if it is relevant in the sense that the expert by reason of specialised knowledge or skill is better qualified to draw an inference from the particular set of facts than the court itself.56 Relevance in this sense can be deemed as one of the core requirements governing the admissibility of expert evidence within the criminal justice system. Relevance generally relates to the ‘probative potential of an item of information to support or negate the existence of a fact or consequence’ (factum probandum).57 Zeffert and Paizes state that relevance essentially relates to a matter of common sense and reason.58 Section 210 of the Criminal Procedure Act reads as follows:59
No evidence as to any fact, matter or thing shall be admissible which is irrelevant or immaterial and which cannot conduce to prove or disprove any point or fact at issue in criminal proceedings.
Du Toit and others similarly state that the relevance of an item of evidence entails its logical ability to show or indicate the material fact for which the evidence is adduced.60 The principle of relevance will play a pivotal role in respect of the admissibility of expert neuroscientific evidence in terms of assessing criminal responsibility. Merely adducing such testimony will not necessarily suffice to comply with the requirement of relevance. Such an opinion may be rendered inadmissible due to the irrelevance thereof. Conversely such an opinion may be admitted if found to satisfy the prerequisite of relevance.
However, the admissibility of expert neuroscientific evidence will be subject to the foundational principles governing expert evidence. There are generally four rules of expert evidence that regulate the reception and admissibility of opinion testimony by experts:61
The first rule relates to the so-called ‘expertise rule’ or ‘specialist’ rule. This rule requires assessment as to whether the witness possesses sufficient knowledge, skill or experience to render him or her an expert who can assist the trier of fact;
The second rule is referred to as the ‘common knowledge rule’ which entails an assessment as to whether the opinion sought from the witness relates to information beyond the ordinary or general knowledge of the court;
The third rule is referred to as the ‘ultimate issue rule’ in which case it has to be assessed as to whether the expert’s opinion will be ‘usurping’ the function of the court;
The fourth rule relates to the so-called ‘basis rule’. This rule requires an assessment as to whether the expert’s opinion is founded on matters within the expert’s own observation.
The rules will also apply to neuroscientists presenting expert evidence. Having regard to the important role that neuroscientific evidence could play in assessing criminal responsibility, in all probability it will pass the relevance yardstick. A court is still, however, in a position to rule such evidence inadmissible should it be found to be irrelevant to the issues before the court.
6. Scientific reliability and validity of neuroscientific evidence: applying the Daubert resolutions
One of the most frequently raised questions or criticisms levelled towards scientific evidence, which in the current discussion pertains to neuroscientific evidence, relates to the scientific reliability and validity of the testimony provided by the scientific expert.
From the outset it should be noted that the terms ‘reliability’ and ‘validity’ are not synonyms but refer to two distinctly different concepts.62
According to Ennis and Litwack, ‘reliability’ refers to ‘the probability of frequency of agreement when two or more independent observers answer the same question’.63
‘Validity’ refers ‘not to how likely psychiatrists are to agree about a particular judgment but to how accurate their judgments are’.64
Another method of assessing the essential difference between reliability and validity is by defining reliability as denoting the degree of correlation or correspondence amongst professionals employing the same method, whereas validity denotes the degree of correlation or correspondence between the judgment derived at by professionals and some fact in the external world.65
The question that still needs to be addressed is whether set criteria should be established in terms of which scientific reliability and validity can be assessed.
It is trite that even where criteria are formulated in terms of which reliability and validity can be measured, the application thereof will fluctuate, as each case will present its own distinct characteristics. It is further important to bear in mind the divergent opinions which can ensue in respect of the mental state of an individual. Relative criteria will, however, assist the trier of fact in making a determination in respect of validity and reliability.
Probably one of the most influential American decisions relating specifically to scientific reliability and validity of expert evidence is the case of Daubert v Merrell Dow Pharmaceuticals.66
Regarding the question of admissibility of expert scientific testimony, a three-staged approach was suggested providing for the following:67
A trier of fact should first assess whether an expert is presenting scientific evidence;
A trier of fact then has to assess whether such evidence will be likely to assist the court to comprehend or ascertain a fact which is in issue in the trial;
To ensure the abovementioned two criteria, the trier of fact has to assess:68
whether the reasoning or methodology underlining the testimony is scientifically valid; and whether that reasoning or methodology can properly be applied to the facts in issue.
Regarding the assessment of scientific reliability and validity, the Supreme Court outlined four factors to be considered as a contextual framework in terms of which reliability and validity can be evaluated. These indicia constitute the following:69
In the first instance, for a theory or technique to constitute scientific knowledge, it should be established whether the theory or technique can be tested or ideally has been tested;
Secondly, a court should ascertain as to whether the theory or technique has been subjected to peer review and publication. Although publication does not ensure evidentiary reliability, it becomes relevant as it indicates that the knowledge has been subjected to the scrutiny of other experts in the field which inadvertently increases the likelihood that problems in the knowledge would have been detected.70
It was recommended that trial courts have due regard to the known or potential error rate for the knowledge and standards prescribing the manner in which the technique is to be applied;
It should also be determined whether the methodology is generally accepted in the relevant scientific community where similar concepts are applied. General acceptance could thus still have an influence in respect of the inquiry into the validity of scientific evidence.
These factors should be considered pertaining to the question of scientific validity with reference to the specific context of the issues raised in a specific case. Factors such as vigorous cross-examination of opposing evidence and due consideration of the burden of proof were held to be adequate to deal with insufficient scientific evidence presented at a trial.71
Carson and Bull elaborate on an important aspect enunciated in Daubert: the principle of causation which could also be useful pertaining to expert testimony in cases where neuroscientific evidence is presented in support of a defence of criminal incapacity.72 Carson and Bull distinguish ‘general causation’ from ‘specific causation’ present in expert testimony. General causation refers to the assertion that one factor can produce particular results. Specific causation refers to those factors having had those results pertaining to the specific case before the court.73 Within the context of criminal incapacity, for example, and more specifically, pathological criminal incapacity, the general causation will denote whether schizophrenia can induce a particular result; whereas specific causation will entail whether schizophrenia had or produced those results in the specific case at hand. The dichotomy of general and specific causation is prevalent in almost all forms of scientific evidence.74 To date there has been no South African decision where the scientific reliability and validity of neuroscientific evidence has been addressed. However, the Daubert indicia could become useful in terms of assessing the scientific reliability and validity of neuroscientific evidence.
7. Medicolegal issues
The presentation of neuroscientific evidence in order to assess criminal responsibility presents South African criminal law with a multifaceted challenge. It was indicated above that neuroscience has made great strides in establishing correlates between neurological or brain dysfunctions and criminal behaviour. The first issue which arises is the question as to what the role of this evidence would be in respect of defences under South African criminal law. It is trite that a neurological dysfunction, for example, a brain tumour or even undiagnosed epilepsy, can lead to involuntary action, in which event the accused would not have acted for purposes of South African criminal law provided the neurological disorder caused the involuntary act. In such event the accused will be exonerated. The more complex situation where neuroscience could play a role is in respect of the defence of pathological criminal incapacity. It was noted above that the threshold requirement for this defence relates to the existence at the time of the offence of a mental illness or mental defect which caused the accused to either lack cognitive or conative capacities. The problem that arises is that a brain disorder will not necessarily qualify as a mental illness or mental defect, albeit that it is quite clear that such a disorder could impact on either the cognitive or the conative capacity of an accused at the time of the commission of the offence. A related issue concerns a situation similar to the factual scenario at the outset of the contribution. If an accused suffered from a brain tumour, for example, which is later healed as a result of neurological intervention, the accused will not be mentally ill as required in terms of s 78(1).
Neuroscientific evidence will, in addition, have to establish that the neurologic disposition was the cause of the incapacity at the time of the crime. Neuroscientific evidence will further have to pass scientific reliability and validity tests in order to be admissible in whichever capacity it is adduced.
8. Diminished criminal capacity: a more plausible option?
South African criminal law does not, as yet, have a specific defence of diminished criminal capacity. The principle of diminished criminal capacity or responsibility is, however, enshrined in s 78(7) of the CPA, which provides that if a court finds that an accused was criminally responsible, but his or her capacity to appreciate the wrongfulness of the act or to act in accordance with such appreciation was diminished as a result of the mental illness or mental defect, it must have regard to such diminished responsibility during sentencing.75 A person may very well suffer from a mental illness or mental defect but still be able to appreciate the wrongfulness of his or her act or to act in accordance with such appreciation albeit that one of these capacities was diminished at the time of the commission of the crime. Diminished criminal capacity will not exonerate an accused but will serve in mitigation of sentence. The role of neuroscientific evidence at present will probably be best suited when advanced in support of mitigation of punishment. It could be argued that due to a neurological or brain dysfunction, an accused’s cognitive or conative capacities were impaired. It could be argued that legislative intervention is needed within the framework of s 78 as discussed above to provide for ‘other’ disorders and concomitantly to provide for the adducing of scientific evidence other than psychiatric and/or psychological evidence. The latter could aid both the prosecution and defence in presenting their cases more comprehensively and accurately.
9. Conclusion
The field of neuroscience has evolved drastically of late. Research clearly indicates that there are correlates between brain dysfunction and criminal behaviour. To date there has been no decided criminal case law in South Africa where neuroscientific evidence was assessed. It remains to be seen whether this evidence will feature and if so to what extent it will have probative value and be admitted. Law and medicine have one common denominator – they are both inexact sciences in a constant state of evolution. As such, courts should be receptive to hearing such evidence even if only to add to other evidence in order to place them in a better position to adjudicate on issues relating to criminal responsibility. It should by no means usurp the function of the trier of fact. At the end of the day, the Constitution of South Africa76 in terms of s 35(3) grants every accused person the right to adduce and challenge evidence. Only when all relevant and admissible evidence has been placed before the court and been thoroughly tested under cross-examination can it truly be said that justice has been served.
Notes
OD Jones as quoted in EA Page, ‘The Criminal Mind: Neuroscientific Evidence as a Mitigating Factor in Sentencing in New South Wales, Australia’ (2017) Washington International Law Journal 659.
JM Burns and RH Swerdlow, ‘Right Orbitofrontal Tumor with Pedophilia Symptom and Constructional Apraxia Sign’ (2003) Archives Neurology 437, 440 as quoted in U Moaz and G Yaffe, ‘What Does Recent Neuroscience Tell Us About Criminal Responsibility’ (2015) Journal of Law and Biosciences 121.
Burns and Swerdlow (n 2) 440.
Burns and Swerdlow (n 2) 440.
L Klaming and BJ Koops, ‘Neuroscientific Evidence and Criminal Responsibility in the Netherlands’ in Spronger (ed), International Neurolaw: A Comparative Analysis (Heidelberg: Springer 2012) 227–56; GM Gkotsi and J Gasser, ‘Critique of the Use of Neuroscience in Forensic Assessments: The Issue of Criminal Responsibility’ (2016) 81 L’evolution Psychiatrique 25–36; ES Compton, ‘Not Guilty by Reason of Neuroimaging: The Need for Cautionary Jury Instructions for Neuroscience in Criminal Trials’ (2010) Vanderbilt Journal of Entertainment and Technology Law 333; E Bennett, ‘Neuroscience and Criminal Law: Have We Been Getting It Wrong for Centuries and Where Do We Go From Here?’ (2018) Fordham Law Review 437–51; FX Shen, ‘Neurolegislation: How US Legislators Are Using Brain Science’ (2016) Harvard Journal of Law & Technology 495–526; EA Page, ‘The Criminal Mind: Neuroscientific Evidence as a Mitigating Factor in Sentencing in New South Wales, Australia’ (2017) Washington International Law Journal 659–91; A McCullough, ‘The Possibilities and Perils of Neuroscience in Criminal Law’ (2016) American Criminal Law Review 47; U Moaz and G Yaffe, ‘What Does Recent Neuroscience Tell Us About Criminal Responsibility?’ (2015) Journal of Law and Biosciences 120–39; RE Redding, ‘The Brain-disordered Defendant: Neuroscience and Legal Insanity in the Twenty-first Century’ (2006) American University Law Review 51–120; S Schleim, ‘Brains in Context in Neurolaw Debate: The Example of Free Will and “Dangerous” Brains’ (2012) International Journal of Law and Psychiatry, Elsevier 104–11; S Kaliski, ‘“My Brain Made Me Do It” – How Neuroscience May Change the Insanity Defence’ (2009) South African Journal of Psychiatry 4–6; JM Fabian, ‘Neuropsychological and Neurological Correlates in Violent and Homicidal Offenders: A Legal and Neuroscience Perspective’ (2010) Aggression and Violent Behavior 209–23; G Yaffe, ‘Neurologic Disorder and Criminal Responsibility’ in JL Bernat and R Beresford (eds), Handbook of Clinical Neurology – Ethical and Legal Issues in Neurology, Elsevier (2013) 345–256; GM Gkotzi and J Gasser, ‘Neuroscience in Forensic Psychiatry: From Responsibility to Dangerousness – Ethical and Legal Implications for Using Neuroscience for Dangerousness Assessments’ (2016) International Journal of Law and Psychiatry, Elsevier 58–67.
Klaming and Koops (n 5) 227.
Page (n 5) 660.
Klaming and Koops (n 5) 227.
Klaming and Koops (n 5) 227.
Klaming and Koops (n 5) 227–29.
Klaming and Koops (n 5) 227–29.
Klaming and Koops (n 5) 227–29.
Shen (n 5) 499.
McCullough (n 5) 48.
MS Gazzaniga, ‘What is Cognitive Neuroscience’ in AS Mansfield (ed), A Judge’s Guide to Neuroscience: A Concise Introduction (2010) 2 as quoted in Bennett (n 5) 441.
Page (n 5) 660.
Page (n 5) 660.
Compton (n 5) 334.
Compton (n 5) 334.
Compton (n 5) 334.
Compton (n 5) 339.
Compton (n 5) 339.
Compton (n 5) 339.
Compton (n 5) 339. See also OC Snead, ‘Neuorimaging and the “Complexity” of Capital Punishment’ (2007) N.Y.U.L.Rev 265.
Compton (n 5) 339.
Compton (n 5) 340.
Compton (n 5) 341.
Compton (n 5) 341.
Compton (n 5) 343. It is interesting to note that in the well-known case of United States v Hinckley 525 F Supp 1342, 1348 (D.D.C. 1981) the defence presented evidence in the form of CAT scan in order to prove that the defendant may have suffered from an organic brain disease. Hinckley was eventually found not guilty by reason of insanity.
Klaming and Koops (n 5) 231.
Klaming and Koops (n 5) 231.
FM Dosteovsky as quoted in Redding (n 5) 54.
Redding (n 5) 57.
Redding (n 5) 57. See also Klaming and Koops (n 5) 233; A Raine, M Buchsbaum and L Lacasse, ‘Brain Abnormalities in Murderers Indicated by Position Emission Tomography’ (1997) 42 Biological Psychiatry 495–508.
Klaming and Koops (n 5) 233.
Klaming and Koops (n 5) 233.
Redding (n 5) 58.
Redding (n 5) 58.
Redding (n 5) 58. Redding (n 5) 69 notes the following in respect of frontal lobe dysfunction causing impulsive behaviour: ‘there is a disruption in the neural circuit running between the limbic system (especially the amygdala) and the frontal lobes, which is a brain circuit responsible for fear conditioning, stress responses, mood regulation and impulse control’.
Redding (n 5) 73.
Redding (n 5) 73.
Redding (n 5) 75.
Klaming and Koops (n 5) 232–33.
Klaming and Koops (n 5) 232–33.
A Raine, ‘Psychopathy, Violence and Brain Imaging’ in A Raine and J Sanmartin (eds), Violence and Psychopathy (2001) 35 as quoted in Redding (n 5) 117.
Section 78(1) of the Act reads as follows:78 Mental illness or mental defect and criminal responsibility
(1) A person who commits an act or makes an omission which constitutes an offence and who at the time of such commission or omission suffers from a mental illness or mental defect which makes him or her incapable – (a) of appreciating the wrongfulness of his or her act or omission; or (b) of acting in accordance with an appreciation of the wrongfulness of his or her act or omission.
CR Snyman, Criminal Law (6th edn, LexisNexis 2014) 164; J Burchell and J Milton, Principles of Criminal Law (3rd edn, Juta 2005) 373.
Snyman (n 47) 164; Burchell and Milton (n 47) 377.
Snyman (n 47) 164.
Snyman (n 47) 164; Burchell and Milton (n 47) 377.
Snyman (n 47) 165; Burchell and Milton (n 47) 380–81.
Snyman (n 47) 165; Burchell and Milton (n 47) 381.
R Slovenko, ‘The Meaning of Mental Illness in Criminal Responsibility’ (1984) 5 Journal of Legal Medicine 1, 4.
DJ Zeffert and AP Paizes, The South African Law of Evidence (2nd edn, LexisNexis 2009) 310–12; PJ Schwikkard and SE Van der Merwe, Principles of Evidence (3rd edn, Juta 2009) 87–88.
Zeffert and Paizes (n 54) 237–43.
Zeffert and Paizes (n 54) 237–43.
Zeffert and Paizes (n 54) 237–43.
Zeffert and Paizes (n 54) 237–43.
Criminal Procedure Act 51 of 1977.
E Du Toit and others, Commentary on the Criminal Procedure Act (Juta 2012) 24–12.
I Freckelton, Expert Evidence: Law, Practice, Procedure and Advocacy (Thomson Reuters 2019).
See, in general, BJ Ennis and TR Litwack, ‘Psychiatry and the Presumption of Expertise: Flipping Coins in the Courtroom’ (1974) California Law Review 693–745, 694–99; IM McKay, ‘Scientific Reliability of Psychiatric Expert Witness Testimony Involving the Use of Classifications from the Diagnostic and Statistical Manual of Mental Disorders’ (1992) Criminal Justice Journal 345–86; T Rogers, ‘Diagnostic Validity and Psychiatry Expert Testimony’ (2004) International Journal of Law and Psychiatry 281–90; D Faust and J Ziskin, ‘The Expert Witness in Psychology and Psychiatry’ (1988) Science 31–35. See also Freckelton (n 61).
Ennis and Litwack (n 62) 697.
Ennis and Litwack (n 62) 697. See also L Meintjes-Van der Walt, ‘Expert Evidence in the Criminal Justice Process: A Comparative Perspective’ (Diss doct, Leiden University 2001) 206–207 where it is noted that the Oxford English Dictionary defines ‘reliability’ as ‘the quality of being reliable’ which is defined as ‘that may be relied upon, in which reliance or confidence may be put; trustworthy, safe, sure’. ‘Validity’ on the other hand is defined as ‘the quality of being wellfounded on fact, of established on sound principles, and thoroughly applicable to the case or circumstances; soundness and strength (of argument, proof, authority, etc.)’.
Ennis and Litwack (n 62) 697–98.
Daubert v Merrell Dow Pharmaceuticals 509, U.S. 579 (1993).
Daubert v Merrell Dow 592–93.
Daubert v Merrell Dow 592–93.
Daubert v Merrell Dow 594.
B Block, ‘Science and the Law in the Wake of Daubert’ (1994) Texas Law Review 757.
DL Shapiro, ‘Criminal Responsibility Evaluations: A Manual for Practice’ (1999).
D Carson and R Bull, Handbook of Psychology in Legal Contexts (2003) 376.
Carson and Bull (n 72) 376.
Carson and Bull (n 72) 376.
Burchell and Milton (n 47) 400–402; Snyman (n 47) 165–66. See also S v Mnisi 2009 (2) SACR 227 (SCA).
Constitution of South Africa, 1996.
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Geert Philip Stevens has declared no conflicts of interest.
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This article does not contain any studies with human participants or animals performed by the author.
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