March 19, 2016
Humans brains are hardwired for altruism, study finds
The human brain appears to be hard-wired to instinctively do good, according to new research from UCLA neuroscientists that could also ultimately lead to a way to “cure” those people who do not possess such altruistic instincts, the university said Friday in a statement.
As part of their work, Leonardo Christov-Moore, a postdoctoral fellow at the university’s Semel Institute of Neuroscience and Human Behavior, and UCLA psychiatry professor Marco Iacoboni analyzed the regions of the brain responsible for our controlling empathetic impulses, while also briefly disabling other opposing parts of the brain.They found that altruistic behavior “may be more hard-wired than previously thought,” Christov-Moore said, and found a possible way to make people behave less selfishly, Iacoboni added. The findings have been published in the February edition of the journal Human Brain Mapping, and a second study based on their work appeared in an early March issue of Social Neuroscience.
Iacoboni called the findings “potentially groundbreaking,” and the authors believe it may finally put to rest the longstanding philosophical debate pitting Jean-Jacques Rousseau’s theory of the “noble savage” versus Thomas Hobbes’ notion that mankind is, at its core, a selfish creature that needs civilization in order to control their base impulses.
Generosity linked to specific areas of the human mind
During their first study, the UCLA neuroscientists recruited 20 people and showed each of them video footage of a hand being poked with a pin. Participants were then asked to imitate photos of faces displaying a wide range of emotions, including happy, sad, angry and excited, while having their brains scanned with functional magnetic resonance imaging (fMRI).
Christov-Moore and Iacoboni monitored activity in several parts of the brain, including a cluster containing the amygdala, somatosensory cortex and anterior insula that previously was linked to pain-related experiences and emotions and with imitating other people. They also observed a pair of areas in the prefrontal cortex, which helps control impulses and regulate our behavior.
Later, participants were asked to play the dictator game, in which they were provided with some money and told that they could either keep it or share it with a stranger. Each person was given $10 per round for a total of 24 rounds. Recipients were actual residents of Los Angeles who had their identities altered for the purpose of the game, but not their ages or income levels.
Afterwards, the participants payouts were compared to their fMRI scans, and the authors found that those who had the most activity in their prefrontal cortex turned out to be the least generous, giving others an average of just $1 to $3 per round. However, one-third of those who had strong responses in the other brain cluster were the most generous, giving away up to 75 percent of their money on average, according to Christov-Moore and Iacoboni.
“It's almost like these areas of the brain behave according to a neural Golden Rule,” explained Christov-Moore. “The more we tend to vicariously experience the states of others, the more we appear to be inclined to treat them as we would ourselves.”
Inhibiting prefrontal cortex activity could make people less selfish
In the second study, the researchers set out to determine if the regions of the prefrontal cortex most active in the stingiest study participants might be blocking the altruistic mirroring impulse found in the cluster containing the amygdala, somatosensory cortex and anterior insula.
They recruited another 58 individuals and subjected them to theta-burst Transcranial Magnetic Stimulation, a non-invasive procedure that temporarily blocks activity in specific regions of the brain. Each participant underwent the procedure for 40 seconds. In a control group of 20 people, a part of the brain associated with sight was weakened on the basis that it would likely have no impact on generosity. In the others, either the dorsolateral prefrontal cortex or the dorsomedial prefrontal cortex , which combine to block a variety of impulses, were inhibited.
As Christov-Moore explained, if people were selfish by nature, weakening those parts of the brain should have made them act even more selfishly. In readily, the opposite happened, with members of this group turning out to be 50 percent more generous than members of the control group. Those who had the dorsomedial prefrontal cortex dampened were more generous on the whole, while those who had activity inhibited in their dorsolateral prefrontal cortex were more giving to people with higher incomes – those who appeared to need the help the least.
“Normally, participants would have been expected to give according to need, but with that area of the brain dampened, they temporarily lost the ability for social judgments to affect their behavior. By dampening this area, we believe we laid bare how altruistic each study participant naturally was,” Christov-Moore said. He and Iacoboni believe that their findings could lead to new, noninvasive ways to increase empathy, especially among those who may have experienced desensitizing events such as those that take place during wartime or in prison.
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