The moral brain

morals.jpgWhere and how is human morality processed and represented by the brain? A freely available review by Jorge Moll and colleagues in the latest issue of Nature Reviews Neuroscience proposes a new model based on neuroimaging and clinical data – the event-feature-emotion complex framework (EFEC) – that makes specific predictions about the kinds of moral impairment that will follow from damage to different brain regions.

In contrast with earlier models that have advocated the idea of a rational prefrontal cortex suppressing our amoral emotional drives, the EFEC framework posits a more integrative three-way system, whereby the prefrontal cortex stores information about moral values, social interactions and expected outcomes, the emotional limbic system codes for the reward value of our behavioural choices, and the superior temporal sulcus allows us to extract relevant functional and social features from the environment, like a sad face or aggressive gesture.

The review gives the example of localised cognitive processes that would occur in response to the sight of an orphan girl. The prefrontal cortex will predict the kind of life the girl is likely to have, the superior temporal sulcus will detect the sadness in her face and body language, and recognise her helplessness, and the limbic regions will give rise to feelings of sadness, anxiety and attachment. Taken together, “these component representations give rise to a ‘gestalt’ [unified] experience by way of temporal synchronisation”, the authors say.

The framework allows for specific predictions to be made about the behavioural and cognitive consequences of dysfunction to these brain areas, depending on whether such impairment occurs developmentally or is acquired later in life. So, for example, an adult who acquires damage to the posterior superior temporal sulcus would be expected to lose the ability to recognise the socially-relevant aspects of people’s facial expressions and body language, and so their moral behaviour dependent on the detection of these signals would be impaired. But their moral reasoning and understanding of social rules would remain intact and they could say how one ought to behave if questioned about situations verbally. In contrast, early developmental disorders affecting this brain region – autism, perhaps – would actually impair the acquisition of social knowledge and social rules.

Presenting concise summaries of other models (including ‘conflict processing’ accounts; Antonio Damasio’s ‘Somatic Marker Hypothesis’; the ‘social response reversal model’; sociopathy as a failure of theory of mind; the ‘structured-event-complex framework’, and the ‘moral sensitivity hypothesis’), the review argues for the favourable utility of the EFEC framework.

Now the EFEC framework can be used to guide the design of future experiments, the authors say. “Understanding the neural basis of moral cognition will help to shape environmental, psychological and medical intervention aimed at promoting prosocial behaviours and social welfare”, they conclude.

Link to review (free, but requires registration)

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