Neuroscience, free will, and moral responsibility
Authors: Callender John S. 
Published: February 2013

Over the past 20 years, we have seen an exponential growth in neuroscience research. The techniques of neuroscientific investigation were initially developed as aids to medical diagnosis and tools for research into pathological brain processes. Brain imaging techniques now have sufficient spatial and temporal resolution to detect changes in brain activity and structure that are psychologically meaningful. We are now able to determine with some accuracy the location of higher brain functions such as memory, emotions, and various types of cognition. This has led to the extension of neuroscience research beyond investigation of disease in the narrow sense of the term, to looking at abnormal behaviors such as addiction and aggression. These techniques have also been increasingly applied to the investigation of healthy brain function and delineation of the neural correlates of activities such as moral decision-making.

The fact that neuroscience is now encroaching on areas that have hitherto been the province of morals and the law creates a new perspective on these issues and brings into focus fundamental questions about matters such as free will, legal capacity, and criminal responsibility.

The ultimate aim of ethical and legal systems is to place constraints on human behavior. Morality and the law aim to promote forms of behavior that are beneficial and to discourage behaviors that are harmful and destructive. With regard to ethics, Pigliucci (2003) argued that a better understanding of the origins and nature of moral behavior will aid ethical advance and that neuroscience can contribute to this. Jones (2006) presented a similar argument in relation to the law. He pointed out that (1) effective law requires an effective behavioral model; (2) the law's existing set of models is essentially incomplete; (3) improving the behavioral models requires the integration of social-science and life-science models of behavior; and (4) such integration requires a familiarity with behavioral biology.

Although there are well-established traditions and extensive literatures on the application of sciences such as psychology and sociology to the law, there may be some factors that create resistance to a neuroscientific contribution to ethics and law. There will be an element of suspicion and resentment on the part of disciplines such as sociology, philosophy, and psychology, which have long histories of influencing morals and the law. There may be concern about bringing biological perspectives to bear on behavior because of the errors and misuses of this approach that have occurred in the past.

There is also an attachment to ‘human exceptionalism,’ that is, a wish to see our moral behavior as something that transcends scientific explanation. There is an intuitive fear that scientific rationalism is potentially all-consuming and that the things that give value and purpose to our lives, such as morality, emotions, and free will be diminished or even negated by scientific scrutiny. There may also be a fear that science and rationalism are potentially dehumanizing. The paradox is that rational thinking is the characteristic that distinguishes us, more than any other, from other creatures and therefore makes us distinctively human.

I will begin this section with discussion of the experiments of Benjamin Libet into the place of conscious intention in the generation of actions. I will then go on to describe some research that has been carried out into the neuroscience of moral decision-making. In the third section, I will look at some of the approaches that have been taken to neuroscientific research into antisocial behavior and other forms of wrongdoing. (Neuroscientific research into psychopathic personality disorder is discussed in Section 8.3). I will conclude by trying to say something about what all this might mean for our future approaches to moral and legal responsibility and to punishment.