Wednesday, March 21, 2007

The robotic ape: Morality and the ventromedial prefrontal cortex

Persons with damage to the ventromedial prefrontal cortext behave more like Mills and less like Kant (emphases mine):
Study Finds Brain Injury Changes Moral Judgment - New York Times

... findings, published online by the journal Nature, confirm the central role of the damaged region — the ventromedial prefrontal cortex, which is thought to generate social emotions, like compassion.

Previous studies showed that this region was active during moral decision-making, and that damage to it and neighboring areas from severe dementia affected moral judgments. The new study seals the case by demonstrating that a very specific kind of emotion-based judgment is altered when the region is offline. In extreme circumstances, people with the injury will even endorse suffocating an infant if that would save more lives.

“I think it’s very convincing now that there are at least two systems working when we make moral judgments,” said Joshua Greene, a psychologist at Harvard who was not involved in the study. “There’s an emotional system that depends on this specific part of the brain, and another system that performs more utilitarian cost-benefit analyses which in these people is clearly intact.”...

...The new study focused on six patients who had suffered very specific damage to the ventromedial area from an aneurysm or a tumor. ...The area in adults is about the size of a child’s fist.

People with this injury can be lucid, easygoing, talkative and intelligent, but blind to subtle social cues, making them socially awkward. They also have some of the same moral instincts that others do.

... All three groups also strongly rejected doing harm to others in situations that were not a matter of trading one certain death for another. They would not send a daughter to work in the pornography industry to fend off crushing poverty, or kill an infant they felt they could not care for.

But a large difference in the participants’ decisions emerged when there was no switch to flip — when they had to choose between taking direct action to kill or harm someone (pushing him in front of the runaway boxcar, for example) and serving a greater good.

Those with ventromedial injuries were about twice as likely as the other participants to say they would push someone in front of the train (if that was the only option), or to poison someone with AIDS who was bent on infecting others, or suffocate a baby whose crying would reveal to enemy soldiers where the subject and family and friends were hiding...

...The ventromedial area is a primitive part of the cortex that appears to have evolved to help humans and other mammals navigate social interactions. The area has connections to deeper, unconscious regions like the brain stem, which transmit physical sensations of attraction or discomfort; and the amygdala, a gumdrop of neural tissue that registers threats, social and otherwise. The ventromedial area integrates these signals with others from the cortex, including emotional memories, to help generate familiar social reactions.

... This tension between cost-benefit calculations and instinctive emotion in part reflects the brain’s continuing adjustment to the vast social changes that have occurred since the ventromedial area first took shape. The ventromedial area most likely adapted to assist the brain in making snap moral decisions in small kin groups— to spare a valuable group member’s life after a fight, for instance. As human communities became larger and increasingly complex, so did the cortical structures involved in parsing ethical dilemmas. But the more primitive ventromedial area continued to anchor it with emotional insistence an ancient principle: respect for the life of another human being.
It's hard not to wonder what a similar study would find find on adult genetic relatives of children with autism. The study is too small to be persuasive on its own, but it's just another in a flurry of recent research that hammers home the reality that we are our brains, and that we have more in common with science fiction robots than we once fancied. Pull out our emotion chip and we switch to a relatively "cold-blooded" judgment system. Disable that, and you probably get a sociopath. I would wager that a successful sniper has a relatively inactive VPC.

Eventually we'll discard the illogical concept of 'individual responsibility'. I wonder if I'll live long enough to see what will replace it ...

1 comment:

Ajlouny said...

"Pull out our emotion chip and we switch to a relatively "cold-blooded" judgment system."

Not to get philosophical on anyone, but it's interesting that you said this, because I often wondered if the soul is the motivator on our actions or is it our brain. And when there is injury to the brain, where does your soul fit in.