Psychopathy and Responsibility: Empirical Data and Normative Judgments

Psychopathy is one of the most frequently cited disorders in discussions of moral and criminal responsibility. Many philosophers and psychologists have argued that psychopaths’ impaired capacity for empathy, diminished responses to fear-inducing stimuli, and failure to conform to social norms indicate that they are not responsible for their actions. In “Philosophers on psychopaths: A cautionary tale in interdisciplinarity,” Jarkko Jalava and Stephanie Griffiths (2017) cite psychological data from case studies, the moral/conventional distinction task, fear conditioning and facial affect recognition experiments in arguing that philosophers systematically misinterpret or simplify the data to support their conclusions about psychopaths’ responsibility. Jalava and Griffiths state that “inconsistent but suggestive data do not imply merely reduced responsibility, nor do they allow for tentative conclusions about responsibility. Any responsibility claim on the basis of these data is equally suspect” (2017, p. 9). Although the authors are right to point out the need for philosophers to be more circumspect in drawing inferences from the results of psychology experiments to responsibility judgments, their claims are too strong and not supported by their discussion. Moreover, it is unclear what the implications of the inconclusive nature of empirical data on psychopaths are for the actual practice of holding people morally and criminally responsible for their behavior.

Much of the recent empirical evidence influencing philosophers’ claims about psychopaths’ diminished responsibility is from neuroimaging studies. Curiously, the authors do not include these among their data sources. At least one study involving magnetic resonance imaging (MRI) has shown a reduction in gray matter volume in brain regions associated with empathic processing, prosocial emotions, and moral reasoning in violent criminal psychopaths compared with normal controls (Gregory et al., 2012). Some functional magnetic resonance imaging (fMRI) studies have shown functional abnormalities in pathways between the amygdala and ventromedial prefrontal cortex, which also mediate the capacity for moral reasoning (Blair, 2007, 2013). Correlations between brain abnormalities and psychopathic behavior do not imply that the first cause the second. Yet if the abnormalities are consistent with a pattern of behavior indicating impairment in the relevant mental capacities, then the imaging data may support tentative conclusions about responsibility. Although imaging data alone would not provide sufficient evidence that an individual lacked or was impaired in these capacities, the data might confirm such a judgment made on the basis of the individual’s behavior. Provided that it supplements rather than supplants behavioral evidence, neuroimaging may provide helpful information about the functional or dysfunctional neural bases of that behavior and can be used legitimately as one factor in assessing responsibility. Even if philosophers overstate correlations between particular brain features and behavior, they are not alone in doing this. Social scientists have claimed on the basis of neuroscientific evidence that highly psychopathic individuals are not responsible and should not be punished for their criminal behavior (Glenn & Raine, 2014). It is unfair to single out philosophers for drawing these conclusions too easily.

In their critique of philosophers’ reliance on empirical data to argue that psychopaths are not responsible or have reduced responsibility because they are impaired in the necessary mental capacities, the authors say nothing about the reliance of some social scientists on this data to argue that psychopaths are responsible. They have but fail to exercise these capacities (Cima, Tonnaer & Hauser, 2010). If we should be skeptical of claims about psychopaths’ diminished responsibility based on studies in experimental psychology, then we should also be skeptical of claims about full responsibility based on similar studies. If drawing inferences from inconclusive data to negative judgments about responsibility is questionable, then drawing inferences from inconclusive data to positive judgments about responsibility is equally questionable. There is no reason to assume that data suggesting that a psychopath has the mental capacities necessary for responsibility is any more scientifically robust than data suggesting that he or she lacks these capacities. If we rely primarily on experimental data in trying to show that a psychopath is or is not responsible, and if the data are limited in this regard, then this suggests that there are no grounds for...