Morals and the human brain: a working model

Abstract

Morality has been at the center of informal talks and metaphysical discussions since the beginning of history. Recently, converging lines of evidence from evolutionary biology, neuroscience and experimental psychology have shown that morality is grounded in the brain. This article reviews the main lines of investigation indicating that moral behavior is a product of evolutionary pressures that shaped the neurobehavioral processes related to the selective perception of social cues, the experience of moral emotions and the adaptation of behavioral responses to the social milieu. These processes draw upon specific cortical-subcortical loops that organize social cognition, emotion and motivation into uniquely human forms of experience and behavior. We put forth a model of brain-behavior relationships underlying moral reasoning and emotion that accommodates the impairments of moral behavior observed in neuropsychiatric disorders. This model provides a framework for empirical testing with current methods of neurobehavioral analysis.

Psychopathy and instrumental aggression: Evolutionary, neurobiological, and legal perspectives

“…The evolution of moral behavior has shaped the functioning of several neural structures (Moll, de Oliveira-Souza, & Eslinger, 2003 , 2007). Many of the structures identified appear to also be associated with psychopathy (Raine & Yang, 2006a).…”

The frontal cortex and the criminal justice system

“…Several well-designed studies have required subjects to do some manner of moral reasoning (to decide what behaviour they would choose in a morally ambiguous situation) versus reasoning about the physical world (for example, considering whether one object is heavier than another). Consistently, the moral reasoning scenario preferentially activates parts of the PFC (Greene et al 2001;Schultz et al 2001;Heekeren et al 2003;Moll et al 2003). Moreover, making a decision in the face of a moral quandary activates more of the PFC than merely contemplating a moral quandary (Moll et al 2002).…”

A neuroscientific approach to normative judgment in law and justice

“…In addition to establishing a target system for intuitive normative judgment, many of the fMRI studies found that brain regions linked with emotional processing are also active during moral judgments (Greene et al 2001;Moll et al 2001Moll et al , 2002aHeekeren et al 2003; for review see Greene & Haidt 2002;Moll et al 2003). As in the lesion data, the orbitofrontal cortex was often implicated.…”

“…In recent years the thought processes related to social cognition in general (Blakemore et al 2004) and normative judgment in particular (Haidt 2001(Haidt , 2003Casebeer 2003;Casebeer & Churchland 2003;Greene 2003;Pigliucci 2003;Moll et al 2003) have also become a target for this kind of study. The boundary that Hume and Kelsen could not cross is becoming permeable.…”