Friday, May 13, 2011

Does Meditation Make People Act More Rationally?

Posted on: April 20, 2011 1:36 PM, by Josh Rosenau
Via USA Today, we learn about a study showing that people who meditate frequently behave in a more rational manner than non-meditators, and they do so because different parts of their brain take charge of certain kinds of decisions.

The study was based around a common test of rational behavior called the Ultimatum Game. Two people sit at a table. One of them is given a sum of money ($20 in this case), and is told to split that however she wants with the other. Before she makes that decision, the other subject is told that if he rejects the share offered to him, neither player will get any money, but if he accepts his share, they both keep their share of the money.
Experiments like this have been run for 30 years now, and consistently find that people are happy to accept a 50:50 split, but tend to reject the offer of free money when their share of the money drops below some threshold (usually around 70:30). From a purely rational perspective, this is silly. Free money is free money, after all, and how much someone else gets shouldn't make a difference. But it does, because of our sense of fairness, and a desire to punish greed.

That desire is rational in some contexts, but not in the Ultimatum Game. In general, people in large social groups should want to punish greed because selfishness is bad for society. If there's a chance of repeated interactions, that punishment ought to make people more likely to behave fairly in the future. Experiments with social monkeys find a similar recognition of unfairness, and a desire to punish it, and similar behavior has been seen in vampire bats. But in the Ultimatum Game, you only get one shot, and the smart move is to take the free money. Punishing greed serves no purpose there, but people do it consistently.

The researchers decided to see whether "expert meditators" behaved differently from the general public. They recruited 26 practitioners of Buddhist meditation, folks with an average 10 years of practice (ranging from 6 months to 24 years), who lead otherwise secular lives involving a career, family, etc. For comparison, they recruited a demographically comparable group of 40 non-meditators.

They let each of the subjects serve as a responder in the Ultimatum Game. Each responder dealt with a different partner for each round of the game. The partners were confederates of the researchers, tasked with offering standardized splits of the $20 in a randomized order.
Graph of behavior of meditators and nonmeditators in the Ultimatum Game.  Meditators are statistically more likely to accept extremely unfair offers (18:2 and 19:1 splits) than nonmeditators.The control group behaved as is typical in these experiments, with steady declines in acceptance after a 70:30 (14:6) split. Meditators began rejecting offers at the same point, but the rate of their decline leveled off around 50% for very poor offers (18:2 and 19:1), while the control group kept dropping. In other words, they were less willing to punish greedy behavior, and more willing to behave rationally by accepting unfair offers.

The researchers then used fMRI to find out what parts of the brain were activated by these different sorts of offers (fMRI detects areas of the brain with more blood flow and therefore more neural activity). Previous work had explored the neurobiology of the Ultimatum Game, but this study found striking differences between the activation patterns in the control group and in the meditators, with the authors reporting: "Strikingly, there was very little overlap in activity between meditators and controls." Comparing the networks of brain regions activated by unfair offers, they found that the control group matched previous studies' findings, while "In sharp contrast, meditators showed activity in an entirely separate network"

Surprisingly, given that they were behaving more rationally, the meditators "did not draw upon ... regions typically seen for mathematical and logical reasoning. Instead, they drew upon ... areas usually linked to visceral, emotional rather than rational, deliberative functions." Their brain patterns were not those associated with an abstract analysis of the game's logic, but rather matched patterns seen in people contemplating altruistic actions.

As the authors note, this study cannot say whether meditation caused a change in brain activity, or whether people with tendencies toward these more rational (or perhaps altruistic) brain patterns are more likely to become Buddhist meditators. Nor, if these people's brains really did change, can we distinguish whether meditation caused that, or if Buddhist teachings in general might have rechannelled how people think about situations like the Ultimatum Game.

If meditation is retraining the brain, then it's entirely possible that we'd find similar effects from prayer, as other research has found comparable effects on the brain between prayer and meditation. If the trend holds, it may suggest that people who decide to pray or meditate may wind up behaving more rationally than those who reject prayer and meditation as irrational.

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