October 11, 2010

Morality and Neuroscience

The idea that moral cognition as a collection of specialized brain functions is developed by neuroscientists. Morality is not viewed as a new, abstract entity, but as a collection of animal attributes that have evolved over hundreds of millions of years. Human morality is an expression of old social cognitions and motivations that have emerged as a less than perfect human version of primate tendencies such as caring for others while seeking dominance. In primates there is an innate sense of justice that forms the deep foundation of morality. Moral emotions are described: compassion, embarrassment, indignation, guilt, shame, pride, contempt, disgust, anger and gratitude. If you had to chose the most reasonable and pacific members of the primate family, it would be Orangutans or Bonobos, not humans.

Moll suggested that: “moral emotions” result from interactions among values, norms and contextual elements of social situations and are elicited in response to violations or enforcement of social preferences and expectations. Although the contextual cues that link moral emotions to social norms are variable and shaped by culture, these emotions evolved from prototypes found in other primates and can be characterized across cultures. The challenge for moral cognitive neuroscience is that it requires extensive cross-field integration of neuroscience, psychology, evolutionary biology and anthropology, among other areas. In setting the goals of scientific exploration in this field, some central issues should be considered. How does the human moral mind emerge from the interaction of biological and cultural factors? How can the context-dependent nature of moral cognition be explained by neuroscience? How does moral cognition relate to emotion and motivation, and what are their neural substrates?”

Moral cognition involves several cortical regions: the prefrontal cortex (PFC), the medial and lateral orbitofrontal cortex (OFC), the anterior temporal lobes (aTL) and the superior temporal sulcus (STS) region that is involved in social perception. STS damage disrupts the ability to recognize socially relevant perceptual features of faces, body postures and movements. Patients with frontal lobe damage display a range of social disabilities and antisocial behaviors. A lesion of the anterior PFC, for example, impairs moral evaluations that rely on predicting the long-term consequences of actions. Patients with OFC damage display socially inappropriate behaviors; they fail to modify behaviors that produce negative outcomes. One patient, for example, became aggressive and callous towards other people after OFC damage; he failed to recognize facial expressions of anger and disgust. Anterior temporal lobe damage disrupts awareness of more abstract social values that are learned and practiced. Subcortical structures involved in moral cognition are the amygdala, ventromedial hypothalamus, septal area, basal forebrain, and the walls of the third ventricle, rostral brainstem and tegmentum.

The limbic system generates behaviors out of body needs and tends to override other regulators of behavior. If you are starving, you may steal or kill to obtain food. But if you are well-fed, you will obey the rules of supermarkets and pay to obtain food. Dysfunction in the limbic system is expressed as motivational disturbances with disorders of appetite, thirst, sexual drives, social attachment and aggressiveness. Studies of sociopaths reveal abnormalities in all these regions.

From Ethics and Morality by Stephen Gislason