I very much welcome the document by the Royal Society on ‘Neuroscience and the law’. In a short series of articles, I consider the scope for synthesis in these disciplines.

The crux of the legal mens rea in many situations is an intention to act. Neuropsychological theories have offered a number of different theories mostly involving the frontal lobes, how this intention to act based on a decision takes place. One influential theory by Norman and Shallice (1986) proposed a computational model of the selection of routine actions based on competitive activation within a hierarchically organised network of action schemas. An explanation of an “intention to act” depends on a thorough analysis of the question of whether we possess “free will” requires that we take into account the process of exercising that will: the cognitive neuroscience of decision-making. Decision making, which reflects a tendency to think about the consequences of a planned act before engaging in that act.

In another view of how the mind and body might achieve decision-making, Damasio’s “somatic marker hypothesis” provides that, during the pondering of a decision, somatic states are triggered by primary or secondary inducers. Once induced, they participate in two functions. In one they provide a substrate for feeling the induced state. In the other they provide a substrate for influencing or biasing decisions. Most intriguing is that the presence of these somatic states and their influence on decision making and behavior need not be conscious. So while both conscious and unconscious knowledge are contributing to the process of choice, the fact that the generation of somatic states can guide us toward beneficial behaviors without any input from our conscious deliberations indicates that much behavior that seems to be “free will” may be determined by the routine operation of a healthy neural mechanism.

Within this framework, it is entirely possible that impulse control reflects inhibition of a pre-potent act (motor impulse control), or a pre-potent mental image/thought (attentional impulse control). The critical neural region for the mechanism of motor impulse control is the more posterior region of the ventromedial prefrontal cortex, i.e. that involving the anterior cingulate (2,3,4). The critical neural region for the mechanism of attentional impulse control is the lateral orbitofrontal and dorsolateral (inferior frontal gyrus) region (2,3,4). However, decision-making research is a double-edged sword in a conversation about rehabilitation. One the one hand, a deterministic view of the choice process seems to undermine the very idea of rehabilitation. On the other, the more we understand the brain, the greater our ability to design interventions that make the possibility of rehabilitation real for many whom the law writes off today.

Whilst it can be argued that “determined” and “inevitable” are not synonymous, it has been of interest whether abnormalities in free will are something that select individuals are born with. An interesting example of variations in genes that promote abnormal responses to fear inducing behaviors is that of Williams syndrome, a condition that has been recognized for very many years. (5) Aside from the striking physical features of this disorder—short stature, malformation of the heart, and distinctive facial markings— Williams children also possess unusual cognitive and behavioral capacities. They have IQs in the range of 40–100, yet frequently show normal linguistic competence, a heightened ability to recognize faces, and a profound love of music, sound and rhythm. The personality of children afflicted with Williams syndrome is not usual. They tend to be hypersocial, which may be caused in part by their heightened ability to recognize faces. This is a moot point. More significant than hypersociability, these children generally lack approach inhibition, a feature that is present in normal children and adults to varying degrees. Children with Williams Syndrome seem unable to differentiate between those who have kind and friendly intentions towards them and those who harbor evil intentions. This is comprehensively reviewed elsewhere. (6)

Moreover, there exist conditions, for example certain types of brain injury or long-term drug substance misuse, in which an individual can be said to have a disorder of the will. Examples such as these demonstrate that the idea of freedom of will on which our legal system is based is not supported by the neuroscience of decision making. The question of whether the average person who becomes involved with the legal system has ‘normal’ free will therefore becomes a highly relevant question. Though it is by no means true that all people who commit crimes are substance dependent or mentally ill, the fact that substance abuse and mental illness plays a role in the behavior of a large percentage. According to the UK Sainsbury Centre for Mental Health, approximately 70% of prisoners have either a psychosis, a neurosis, a personality disorder, or a substance misuse problem. (7)

On the other hand, other cases of impaired free will exist in neurological conditions exist that result in people essentially ignoring experiences of punishment (8). That the cognitive profile of violent offenders is so similar to that of patients with just these conditions makes us wonder how, whether and to what degree punishment is working as a deterrent with any particular person.

References

(1) Cooper, R, T Shallice. (2000) Contention scheduling and the control of routine activities. Cognitive Neuropsychology 17 (4), 297–338

(2) Bechara, A. (2003). Risky business: Emotion, decision-making and addiction. Journal of Gambling Studies, 19(1), 23–51.

(3) Bechara, A. (2004). Separate neural substrates underlie different mechanisms of performance monitoring and behavioral control. In M. Ullsperger, & M. Falkenstein (Eds.), Errors, conflicts, and the brain: Current opinions on performance monitoring (pp. 55–63). Dortmund: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig.-Munchen.

(4) Bechara, A., & Damasio, A. R. (2005). The somatic marker hypothesis: A neural theory of economic decision. Games and Economic Behavior, 52(2), 336–372.

(5) Albert Galaburda et al. (2001) Dorsal Forebrain Anomaly in Williams Syndrome, 58 Arch Neurol. 1865–1869. See also Allan L. Reiss et al., Brain Imaging in Neurogenetic Conditions: Realizing the Potential of Behavioral Neurogenetics Research, 6 Mental retardation. Developmental Disabilities Research Nev.   186–197 (2000).

Much of what we know about these mechanisms indicates that decision making is greatly influenced by implicit processes that may not even reach consciousness.

(6) The neuroscience of free will. Laurence Tancredi. Behavioral Sciences and the Law Behav. Sci. Law 25: 295–308 (2007)

(7) From the Inside Experiences of prison mental health care Graham Durcan. Sainsbury Centre for Mental Health.

(8) Decision Making and Free Will: a Neuroscience Perspective. Kelly Burns and Antoine Bechara.Behavioral Sciences and the Law. Behav. Sci. Law 25: 263–280 (2007)

 

@legalaware has a Ph.D. in cognitive neuropsychology from the University of Cambridge and a LL.M. in international legal practice from the College of Law.