Is Selfishness A Brain Defect?

By Mark Esposito, Guest Blogger

Duke neuroscientist, Michael Platt, has an intriguing theory. What if altruism isn’t just learned at your mother’s knee but is really a result of evolved brain chemistry? In a study he co-authored and published in the journal, Nature Neuroscience, Platt wondered why certain primates act unselfishly. Animal behaviorists have long known that monkeys will go without food rather than see a member of their species shocked, and mice will starve to avoid hurting other mice. Major news stories around the world  have told the tales of animals risking their own safety to protect humans and other animals. In one recent episode,  Binti Jua, a female gorilla saved a three-year-old boy from other gorillas when he fell into the gorilla enclosure at the Brookline Zoo.  In another, a dog in Chile dodged traffic on a busy freeway to drag his canine companion to safety after it  had been struck and rendered unconscious.

What isn’t known is the basis for this animal “morality.” Some scientists have theorized that this altruism is the result of emotions or simply instinct.  But Platt thinks the answer may lie deep in the recesses of the brain.  Using rhesus monkeys because of their  similarity to humans both anatomically and physiologically, Platt and his colleagues set up a simple experiment.  Monkeys were shown computer images which when correctly identified  resulted in a squirt of tasty juice coming their way. The monkeys quickly caught on that correct answers rendered a direct benefit. Then, the researchers changed the rules of the game. Instead of a correct answer getting the test subject a tasty squirt of juice, it resulted in one for their neighbor. Of course, the monkey had the choice to give no juice to their neighbor at all by simply refusing to play or answer incorrectly. The deciding monkeys consistently showed a pattern of doling out juice to their friends  And lest you think the other monkeys merely liked seeing the juice squirt anywhere, the experiment didn’t work when the scientists replaced the fellow primate with a bottle of juice as the beneficiary.

During the experiment, the scientists connected brain monitors to the monkeys to record any neuronal activity. What they found suggests that brain chemistry plays an important role in just how empathetic the primates behaved.  Platt concentrated his attention on a region of the brain known as the orbitofrontal cortex, which is known to play a role in reward processing. He found that when monkey benefited themselves,  neurons in a region called the anterior cingulate gyrus fired, but when the monkeys helped their friends different cells in the same area fired. Platt suggests that this rendering of pleasure from helping others may serve as the chemical basis for altruism. He even speculates that the finding has carry-over effects to human behavior.  Believing that the orbitofrontal cortex encodes vicarious experiences which account for happiness and sadness, he theorizes that “vicarious experience and reward is perhaps what actually drives giving behavior and perhaps drives charity in people.”

Could the lack of this neuronal activity account for selfishness?  If so, could its utter absence make a human a sociopath? The answer lies down the road but it could have a dramatic impact on the way we view human behavior and hence the consequences for that behavior.

Sources: msnbc and throughout

~Mark Esposito, Guest Blogger