Scanning the Brain for Its Moral Center

A scientist uses brain scans and experiments to find the brain's moral center.


May 2, 2007 — -- As I changed into a surgical gown, I felt an ever increasing sense of anxiety. Even the unrestrained laughter of my producer colleague, who observed me wearing the ill-fitting dress and a pair of huge protective goggles, did nothing to reduce the stress. I was about to undergo my first-ever brain scan.

The purpose was to test the radical assertion of professor Marc Hauser that all of us are born with an instinctive sense of right and wrong. Hauser is a biological anthropologist at Harvard and the author of "Moral Minds: How Nature Designed Our Universal Sense of Right and Wrong."

And Hauser has been using brain scans, along with other experimental tools, to support his thesis.

Hauser, who uses the model of Noam Chomsky's theory of generative grammar, believes that just as humans have evolved a particular quality that enables us to acquire language, we've also developed what he calls "moral grammar."

He has subjected adults to a series of moral dilemmas, while scanning their brains. Hauser noticed that certain parts of the brain, which are traditionally associated with emotion, tended not to react until after a moral judgment had been made.

"I want to make a similar argument that we have acquired through evolution a universal moral grammar that allows us to acquire many possible moral systems," Hauser said. "I think the implication is that we're born with principles that will guide us towards what is right or wrong."

As I lay in the huge MRI scanner at a laboratory in Boston, I was subjected to a number of moral dilemmas. One told the story of Josephine and her younger sister who are playing in the bathroom where a hair straightening iron is resting near the sink.

Josephine's mother has turned the iron off so that it is no longer hot, but Josephine does not know this. She continues to allow her little sister to play by the sink.

I was then asked to respond within four seconds: Josephine allowing her sister to play by the sink was either "forbidden" or "permissible?" I responded to the question in much the same way as previous subjects: I felt that Josephine's decision to allow her sister to continue playing was forbidden.

And just as I made that decision, my own brain responded much as Hauser anticipated. There was a so-called "neural awakening" of the right temporal region each time that I was confronted with a moral dilemma.

According to Hauser's research, every human brain takes on the moral dilemma here first. It is this part of the brain that plays a critical role in the analysis of beliefs, thoughts and desires.

"It's unconscious. It's intuitive," he said. "It's very natural and spontaneous. The view that we have is that, yes we rationalize, yes we experience emotion. But both of those may happen after the moral grammar has done its work, unconsciously."

In addition to scanning adults, Hauser has conducted thought experiments on children -- in one case giving half a school class envelopes containing candy, with the other half receiving nothing.

Each time he has conducted this experiment, in a variety of cultural contexts, Hauser says there is an immediate reaction to the injustice of it all. And then, the children with candy tend to offer half their own candy to those are empty-handed.

Hauser argues that while parents clearly have an effect on their children's developing sense of fairness and justice, it is striking that cultures are so consistent when given the candy test.

"No culture offers less than about 15 percent of the pot and no culture offers more than about 50 percent; further, no culture rejects offers greater than about 20 percent. If this was simply up to education or parental whim, you would expect the values to be all over the place."

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