A primary task for neuroscience is to explain how a two-and-a-half-pound hunk of organic matter produces consciousness intentionality, responsiveness, mental causation, and all the other mental apparatus that is so central to our lives…”[1]

We are witness to an age of tremendous developments in the fields of clinical and theoretical neuroscience. Contemporary advancements continue to provide profound and unprecedented insight into the active workings of the human brain. We now enjoy a growing understanding of a vast array of interrelated conative, cognitive, and affective brain processes associated with emotional regulation, empathy, and moral judgment –  offering the promise of gaining greater clarity and understanding of our nature, and perhaps even who, and what we are. Perhaps most significantly, it is anticipated that these advancements will provide greater understanding about the causes of criminal behaviour. This stands to have tremendous implications for our system of criminal law, and our legal practices.

What follows is meant to provide a brief overview of the landscape of this emerging field. In future posts, the author will consider these advancements in the context of specific issues that have begun to arise on the boundaries of neuroscience and criminal law, in Canada.

Neuroscience Defined

Neuroscience is a field of study concerned with the structure and function of the nervous system, generally the human brain.[2] The term “neuroscience” is not ontologically unique. It encompasses a variety of disciplines that have different applications in the forensic and legal context. In the contemporary criminal law setting, neuroscience is generally defined as a  branch of inquiry that uses technological and theoretic advancements to “illuminate the links between mind and brain, [and] to reveal the brain bases of human behaviour and cognition”.[3]

Novel Brain Imaging Technologies

Advancements in neuroscience have been fueled by the advent of novel brain imaging technologies. Most notable is the development, and refinement of a technology known as functional magnetic resonance imaging (fMRI). fMRI is a procedure which derives time-varying information of neural activity based on blood-flow to various brain regions. This form of brain imaging provides a non-invasive, real-time window into the human brain, and is used to correlate brain activity with the behaviour of test subjects. As Stephen Morse explains, advancements such as fMRI present “hitherto, unimaginable possibilities… for understanding the link between brain and behaviour”.[4]

Brain Imaging and fMRI Studies

Using these novel procedures, neuroscientists and psychologists have undertaken studies that attempt to draw connections between real-time fMRI information and the behaviour of clinical subjects. For example, in one study scientists were able to tell in advance when test subjects had solved certain problems, by fMRI signalling an “aha!” moment in the brain.[5] In other studies scientists have used fMRI to determine the effect of meditation on brain function;[6] considered the difference in brain reactions between introverted and extroverted persons;[7] identify depression, anxiety,[8] and chronic pain;[9] detect early signs of Alzheimer’s disease;[10] study the neurological basis of the lack of empathy in psychopaths;[11] and identify neurocognitive biomarkers related to persistent antisocial behaviour.[12] Further, fMRI is now used in many settings as a means of lie detection, in a novel technology colloquially referred to as “no-lie fMRI” – which claims to be able to identify deception with an extremely high degree of probability.[13]

The Criminal Brain

In recent years, scientists have also accumulated a mass of knowledge about the conative, cognitive, and affective brain processes often associated with emotional regulation, empathy, and moral judgment. In other words, through many of these studies, it has been suggested that we are now beginning to understand what is sometimes described as the ‘moral brain’. The implications of such advancements have the most immediate, and practical application, in the context of our criminal justice system.

Incident to a growing understanding of the ‘moral brain’ is a greater understanding of criminal behaviour. Through brain imaging, scientists have begun to uncover neural correlates and processes associated with anti-social behaviour, impulse control, and tendencies towards violent aggression and sexual misconduct. For example, scientists have now uncovered structural and functional abnormalities associated with psychopathy, a disorder characterised by an underlying emotional dysfuncation typified by a pronounced lack of guilt, remorse and empathy.[14] Studies suggest that this emotional dysfunction arises from low patterns of neural activity and volume in the ventromedial prefrontal cortex[15] and the amygdala.[16]  More recent studies implicate broader regions including the anterior and posterior cingulate and the insula.[17]

It has been suggested these regions form the central core of the ‘moral’ and ‘emotional brain’. They play a key role in social mobilization and the capacity to learn the goodness and badness of objects and actions. It is thought that deficiencies in these regions lie at the root of a host of related anti-social behaviours such as impulsivity, violent instrumentalist aggression, and extremely high rates of criminal recidivism.[18] The identification of the brain bases of these characteristics, and a greater appreciation of their contribution to criminal behaviour, has also lead to novel technologies aimed at altering these behaviours. The ethical implications of such technologies, which involve manipulating brain functions in human subjects, will be the subject of a future post.

Current State of Research and Technology

Many are optimistic about the promise of current research and technologies. It is true that neuroscience shows great promise. Proponents suggest that as neuroscience progresses, the use of brain imaging, such as fMRI, and advanced computer technology will allow scientists to unlock the secrets of the human brain. This, in turn, will allow us to uncover the neurobiological basis of human cognition, morality and unearth the root cause of criminal behavior.[19] Thus, allowing them to dissecting the physical neural workings of the human “mechanism” in the same manner one would analyze a complex circuit system or a computer code.[20] Such beliefs are premised on the assumption that brain states and consciousness are reducible to physical neural processes in our bodies, which are in turn subject to universal physical laws. Such proponents are optimistic that neuroscience will live up to its promise of “turning the black box of the mind into a transparent bottleneck” allowing us omniscient clarity into the expanses of the human mind.[21]

However, many are more cautious in their predictions. They are quick to point out serious limitations of current technologies. There are many difficulties associated with using current imaging technologies to draw definitive links between brain, behaviour and criminal responsibility.[22] Contemporary neuroscience is a relatively young science. It is subject to many limitations. Stephen Morse believes that until we know “vastly more”, neuroscience will not add much to our understanding of criminal responsibility.[23] Others note that when it comes to the workings of the human brain “there are many things, even quite basic things, that we do not know”.[24] As Fyodor Dostoyevsky rightly cautions “the causes of human actions are usually immeasurably more complex and varied than our subsequent explanations of them”.[25]

Neuroscience as Expert Evidence in Canadian Courts

In light of these advancements, there is no question that the next decade will see an increasing tendency to admit novel brain science into court proceedings – particularly in the criminal context. Within our legal institutions, neuroscience evidence will continue to be accepted incrementally, attentive to the current state of the relevant science and technologies. The manner in which Courts will receive this evidence will be governed by laws related to expert evidence, and the admissibility of novel science.

The test for expert evidence in Canada is set out by the Supreme Court of Canada in its decision of R v. Mohan.[26] Before a Court admits expert evidence, it will consider whether a moving party has satisfied four strict criteria:

  1. relevance;
  2. necessity;
  3. the absence of an exclusionary rule; and
  4. suitable qualifications.

The Mohan test has additional components where the proposed expert evidence includes novel science. Science will is ‘novel’ where:

  1. the court does not have an “established practice” of admitting it; or
  2. the court is using an established theory or technique for a new purpose.[27]

Before admitting novel science, Canadian courts require the science to have a “reliable foundation”.[28] Central considerations are whether the theory or technique:

  • can be and has been tested;
  • has been subject to peer review and publication;
  • has a determined or potential rate of error; and
  • has been generally accepted in the scientific community.[29]

The test for expert evidence is contextual. Its relevance is informed by the nature of the proceedings. For example, different considerations would apply in civil proceedings, than in criminal proceedings. The test is also principled.  Fundamental principles of criminal law inform the process – such as the “golden thread” of our criminal system: the presumption of innocence.[30] It is also informed by heightened concern about the devastating injustice of wrongful conviction, and revulsion against the punishment of the “morally innocent”.[31] On this basis, courts will be more prepared to accept expert evidence where it is necessary to address important issues related to guilt or innocence, and moral responsibility.

Finally, the test is reactive to developments in science. It is a general principle of evidence that all probative evidence should be admissible, absent a clear basis in law or policy to exclude it. Like the law, science continues to evolve and develop its base of knowledge. As Justice Binnie states:

A case-by-case evaluation of novel science is necessary in light of the changing nature of our scientific knowledge: it was once accepted by the highest authorities of the western world that the earth was flat.”[32]

Therefore, scholars propose “a flexible, principled case by case approach in which competing policy interests at stake are weighed in the context of the circumstances of a particular case”,[33] in the context of what is observed as a “discernible trend” towards the increased admissibility of expert evidence.[34]

The manner in which novel neuroscience will be admitted in future cases will be an area of heightened importance in coming years. It is difficult to anticipate the exact areas in which this evidence will be introduced. However, it is likely to garner the greatest attention in the field of criminal law.

For example, it stands to reason that, as novel imaging technologies are refined, they will frequently be admitted into criminal trials. Turning to the Mohan criteria, in many cases, such evidence may well satisfy the necessity and relevance requirements. For example, in cases involving dangerous offenders, brain imaging or studies related to risks of recidivism, and the prospects for rehabilitation may benefit greatly from novel technologies and research. In cases where a serious organic brain disorder or underlying psychiatric illness plays a substantial role in the narrative of the offence, novel studies or brain imaging may well speak to the criminal responsibility of an offender, or their degree of moral culpability in the context of sentencing – where the rules of evidence are relaxed.

It is also possible to envision novel studies extending to larger issues. For example, as technologies such as fMRI lie detection, which one study suggested to be accurate in 90% of cases,[35] are further refined, this may precipitate questions about our traditional methods of assessing credibility in criminal proceedings – i.e. whether traditional credibility assessments by triers of fact should supplemented or supplanted by brain imaging.[36]

Further, neuroimaging studies have further illustrated the devastating effects of solitary confinement on the human brain, including structural and functional changes.[37] In these cases, and similar cases, advancements in neuroscience may also call us to reconsider both the effectiveness, and humaneness of our practices of punishment.

Generally speaking, particularly given the troubling prevalence of mental health issues in the criminal justice system, and a growing appreciation of the link between brain and behaviour, in the near future, it is not difficult to imagine that advancements in these areas will pervade some areas of our criminal practices, and possibly precipitating reform.

Looking Forward

Despite the limitations of neuroscience, and these ethical issues future advancements will provide “a genuine opportunity to enrich the legal understanding of human agency and to inform legal responsibility and practices”.[38] In an age of unprecedented scientific and technological advancement in the mind sciences, developments in brain imaging technology stand to revolutionise how we asses criminal responsibility. Our law is not static or unchanging. And neither is our scientific understanding. Like the law, science continues to evolve and develop its base of knowledge. It is not “cast in stone… enacted in a vacuum”,[39] or “frozen in time”.[40]

In many important respects, the normative judgments which influence our legal practice cannot be isolated from what science tells us about how the human brain operates, both in sickness and health. As explored in future posts, these issues arise routinely in cases before the Courts in Canada, and a greater understanding of these advancements offer important insight into our current practices.


[1] Stephen Morse, “Lost in Translation?: An Essay on Law and Neuroscience” in Michael Freeman, ed., Law and Neuroscience, (2011) Current Legal Issues, Vol. 13, p. 529 at 533.

[2] “Neuroscience, n.”. OED Online. September 2013. Oxford University Press.

[3] Stephen J. Morse and Adina L. Roskies eds. A Primer on Criminal Law and Neuroscience: A Contribution of the Law and Neuroscience Project, Supported by the MacArthur Foundation (Oxford: Oxford University Press, 2013) at 1.

[4] Morse and Roskies, Primer, supra at xv.

[5] John Kounios and Mark Beeman “The “Aha! Moment: The Cognitive Neuroscience of Insight”, Current Directions in Psychological Science, 18, 210-216 cited in Morse and Roskies Primer ibid at xv.

[6] A. Lutz, J.D. Dunne, & R.J. Davidson, “Meditation and the Neuroscience of Consciousness” In P.D. Zelazo, M. Moscovitch, & E. Thompson (Eds.), The Cambridge Handbook of Consciousness, (Cambridge: Cambridge University Press, 2005).

[7] T. Canli, et al, (2001). “An fMRI Study of Personality Influences on Brain Reactivity to Emotional Stimuli” in Behavioral Neuroscience, 115, 33-42.

[8] H.S. Mayberg, et al (1999): “Reciprocal Limbic-Cortical Function and Negative Mood: Converging PET Findings in Depression and Normal Sadness” Am J Psychiatry 156:675–682.

[9] Robert England, “Objective Determination of Chronic Pain in Patients”,(2011) Camporesi & Bottalico

[10] L.K. Laatsch, et al (2004). “Investigating the Neurobiological Basis of Cognitive Rehabilitation Therapy with fMRI.” Brain Injury, 18, 957-974. C.L. Leveroni, et al “Neural Systems Underlying the Recognition of Familiar and Newly Learned Faces.”(2000) The Journal of Neuroscience, 20, 878-886.

[11] Q. Deeley, et al, “Facial Emotion Processing in Criminal Psychopathy: Preliminary Functional Magnetic Resonance Imaging Study” (2006) British Journal of Psychiatry, 189, 533-539.

[12] S.W. Anderson et al. “Impairment of Social and Moral Behavior Related to Early Damage in Human Prefrontal Cortex.” (1999) Nat Neuroscience 2:1032–1037.

[13] See G. Ganis et al. Neural Correlates of Different Types of Deception: An fMRI Investigation” (2003) Cerebral Cortex, 13, 830-836. See also J.R. Simpson, “Functional MRI Lie Detection: Too Good to be True?” J Am Acad Psychiatry Law. 2008;36(4):491-8.

[14] Hare, R. (1999). Without Conscience: The Disturbing World of the Psychopaths Among Us. New York: Guilford Press; Hare, R. (2011). Hare psychopathy Checklist-revised (PCL-R) (2.nd ed.). North Tonawanda, NY MHS, Multi-Health Systems.

[15] The vmPFC is involved in the representation of reinforcement expectancies. It has been suggested these regions form the central core of the “emotional brain” and play a key role in social mobilization, morality, and the capacity to learn the goodness and badness of objects and actions.

[16]The amygadala plays a central role in aversive conditioning, stimulus-reinforcement, instrumental learning, and response to fearful and sad facial expressions.

[17] Anderson, N., & Kiehl, K. (2012), The Psychopath Magnetized: Insights from Brain Imaging in Trends in Cognitive Sciences, supra at 52-60. Some of these deficiencies are thought to have a genetic basis. Research has recently turned attention to the MAOA gene (sometimes called the ‘warrior gene’), which produces the enzyme monoamine oxidase (MAO-A) which regulates the delivery of neurotransmitters such as serotonin and dopamine in the brain. However, MAOA is just one of a list of potential candidate genes associated with psychopathic traits.

[18] Glannon, W. (2014), “Intervening in the Psychopath’s Brain”. Theoretical Medicine and Bioethics, 35(1), 43-57.

[19] Greene, J., & Cohen, J. (2011). For The Law, Neuroscience Changes Nothing And Everything. Oxford Handbooks Online. doi:10.1093/oxfordhb/9780199570706.013.0153; Churchland, P. S. (2011), Braintrust what neuroscience tells us about morality, Princeton, N.J.: Princeton University Press; Wegner, D. M. (2002). The illusion of conscious will. Cambridge, MA: MIT Press; Sen, A.K. (1985). Well-Being, Agency and Freedom: The Dewey Lectures 1984. Journal of Philosophy, 82(4), pp.169–221; Gazzaniga, M. (2005). The Ethical Brain. New York: Dana Press; Mendez, M. (2009). “The Neurobiology of Moral Behavior: Review and Neuropsychiatric Implications”, CNS Spectr 2009 Nov; 14(11): 608–620.

[20]J. Green and J. Cohen, “For the law Neuroscience Changes nothing and everything,” in Law and the Brain, ed. S. Zeki and O. Goodenough (Oxford, U.K.: Oxford University Press, 2006) at pp. 217-218.

[21] Green and Cohen, Neuroscience, supra at 217-18.

[22] Morse, S. (2007) “The non-problem of free will in forensic psychiatry and psychology” Behavioral Sciences & the Law Behav. Sci. Law, 25(2), 203-220. doi:10.1002/bsl.744; Glannon, W., “What Neuroscience Can (and Cannot) Tell Us about Criminal Responsibility” in M. Freeman, ed., Current Legal Issues, volume 13, “Law and Neuroscience” (Oxford: Oxford University Press), 13-28; (2011); Glannon, W. Brain, Body, and Mind: Neuroethics with a Human Face. Oxford: Oxford University Press.

[23] Stephen Morse, “Brain Overclaim Syndrome and Criminal Responsibility: A Diagnostic Note”, (2006) State Journal of Criminal Law, Vol. 3, p. 397.

[24] Belcher and Roskies, Neuroscience Basics, supra at 35.

[25]The Idiot (Oxford: Oxford World Classics, 1998).

[26] [1994] 2 SCR 9 [Mohan].

[27] Paciacco and Stuesser, The Law of Evidence, at 205.

[28] See generally J.L., supra note 32.

[29]R. v. Trochym, 2007 SCC 6 [Trochym] adopting a similar test and reasoning to Daubert v. Merrell Dow Pharmaceuticals Inc., (1993) 509 U.S. 579.

[30]Woolmington v DPP, [1935] UKHL 1.

[31]R. v. Ruzic, 2001 SCC 24.

[32]J.L., supra note 32 at para 25. See also J. Sopinka, S.N. Lederman & A.W. Bryant, The Law of Evidence in Canada, 2nd ed. (Toronto: Butterworths, 1999) at 6-7.

[33] Ibid at 6-7.

[34]Paciocco and Stuesser, The Law of Evidence in Canada, at 7.

[35] Langleben, D. D., & Moriarty, J. C. (2013), “Using Brain Imaging for Lie Detection: Where Science, Law and Research Policy Collide. Psychology, Public Policy, and Law : An Official Law Review of the University of Arizona College of Law and the University of Miami School of Law19(2), 222–234. http://doi.org/10.1037/a0028841

[36] Langleben, D. D., & Moriarty, J. C. (2013). Using Brain Imaging for Lie Detection: Where Science, Law and Research Policy Collide. Psychology, Public Policy, and Law : An Official Law Review of the University of Arizona College of Law and the University of Miami School of Law19(2), 222–234. http://doi.org/10.1037/a0028841

[37] Heidbreder, C.A., I.C. Weiss, A.M. Domeney, C. Pryce, J. Homberg, G. Hedou, J. Feldon, M.C. Moran, and P. Nelson. 2000. Behavioral, neurochemical and endocrinological characterization of the early social isolation syndrome. Neuroscience 100(4): 749–768; Weiss, Isabelle C., Christopher R. Pryce, Ana L. Jongen-Rêlo, Nina I. Nanz-Bahr, and Joram Feldon. 2004. Effect of social isolation on stress-related behavioural and neuroendocrine state in the Rat. Behavioural Brain Research 152(2): 279–295; Bublitz, Jan Christoph, and Reinhard Merkel. 2014. Crimes against minds: On mental manipulations, harms and a human right to mental self-determination. Criminal Law and Philosophy 8(1): 51–77.

[38]Nicole A. Vincent, Neuroscience and Legal Responsibility (Oxford: Oxford University Press, 2013) at 6.

[39]R v. Levogiannis, [1993] 4 SCR 475 at para 22.

[40]Trochym, supra note 56 at para 31.