An "Off-Switch" for Greed

Study Spots the Brain's Selfishness 'Off-Switch'
(article seen on Yahoo - published in the Oct. 6 issue of Science)

Civil society may hinge on a tiny piece of tissue at the front of the human brain, a new study suggests.

Experiments involving a "fairness" game show that the right side of this region -- called the dorsolateral prefrontal cortex -- helps people suppress selfish urges in obviously unjust situations, even at their own expense.

When researchers used a mild electric current to temporarily short-circuit this area, the law of the jungle quickly reasserted itself.

People with disabled right-side dorsolateral prefrontal cortexes grabbed whatever money they could from lopsided transactions -- even when they knew the deal they were getting was grossly unfair.

"They understood the unfairness of it all, but they simply couldn't inhibit their need for getting the money," said Paul Sanberg, director of the Center of Excellence for Aging and Brain Repair at the University of South Florida College of Medicine in Tampa....

The Swiss and American team behind this research noted that, despite a long history of crime, wars and rapaciousness, human beings are innately cooperative. In fact, Homo sapiens is the only species to exhibit "reciprocal fairness" -- the punishment of others' unfair behaviors, even in situations where doing so hurts the punisher....

The experiment shows that this part of the cortex "is clearly very important for our social behavior, our societal evolution," Sanberg said. The right side of the DLPFC helps people resist those strong urges for sex, money and general acquisitiveness that come from more primitive sites outside the cortex, he said.

"It provides modulation of those urges, so that you can have control over them," Sanberg added. "As we evolved, we somehow developed this control over our basic needs."

One intriguing line of research is whether the right-side DLPFC functions similarly in everyone -- even hardened criminals or sociopaths.

"This is a very interesting question which we are just exploring now," Fehr said. "Preliminary results suggest that the right DLPFC has very different activation across individuals."