Morality is a slave to emotion

Damage to one part of the brain can leave some types of impersonal judgment intact, but radically alter decisions when emotional issues are at stake.

Certain brain damage can radically alter decisions of a moral nature, highlighting the link between morality and emotion, say U.S. researchers. – iStock

PARIS: Damage to one part of the brain can leave some types of impersonal judgement intact, but cause surprising reactions when emotional issues are at stake, say U.S. researchers.

The new findings shed light on how damage to the brain’s emotion centres can also affect our capacity for moral decision making, highlighting the role of emotions in determining right and wrong.

Investigators led by Ralph Adolphs of the California Institute of Technology recruited 30 men and women to answer 50 carefully selected series of hypothetical questions.

The questions fell into three categories: non-moral choices, for instance about shopping; moral impersonal decisions such as, would you keep money from a wallet you found on the pavement?; and personal moral scenarios, such as: would you kill a single human if it was the only way to save many others?

Six of the volunteers had sustained damage to the ventromedial prefrontal cortex, or VMPC, a small brain region located just behind the forehead, which is key to processing moral judgements. Twelve had brain damage elsewhere, while the other 12 had no brain damage.

There was no difference among the volunteers in their responses to non-moral and moral impersonal decisions. But the volunteers with VMPC damage stood out remarkably in the personal moral scenarios.

They plumped swiftly and decisively for “utilitarian” decisions – they had no problem with harming or sacrificing one individual for the sake of the common good.

The other participants were less likely to do so, and if they did, it was usually after a time was spent pondering the decision. Normally, humans are blocked from harming each other by aversion, a feeling that co-author Antonio Damasio describes as “rejection of the act, but combined with the social emotion of compassion for that particular person”. Aversion, though, was absent among the people with VMPC lesions.

“Because of their brain damage, they have abnormal social emotions in real life. They lack empathy and compassion,” said Adolphs.

The study, published online today in the British journal Nature, not only pinpoints the VMPC as critical circuitry for processing intuition and emotion. It also adds to philosophical debate as to whether humans make moral judgements based on external rules, set by society, or on their own emotions.

Humans, say the authors, may be neurologically unfit for strict utilitarian thinking, because emotion and reason cannot be separated. Indeed, they suggest that neuroscience may be able to assess different philosophies to see how compatible these are with the human brain.

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