Caltech Scientists Develop Novel Use of Neurotechnology to Solve Classic Social Problem

PASADENA, Calif.—Economists and neuroscientists from the California Institute of Technology (Caltech) have shown that they can use information obtained through functional magnetic resonance imaging (fMRI) measurements of whole-brain activity to create feasible, efficient, and fair solutions to one of the stickiest dilemmas in economics, the public goods free-rider problem—long thought to be unsolvable.

This is one of the first-ever applications of neurotechnology to real-life economic problems, the researchers note. "We have shown that by applying tools from neuroscience to the public-goods problem, we can get solutions that are significantly better than those that can be obtained without brain data," says Antonio Rangel, associate professor of economics at Caltech and the paper's principal investigator.

The paper describing their work was published today in the online edition of the journal Science, called Science Express.

Examples of public goods range from healthcare, education, and national defense to the weight room or heated pool that your condominium board decides to purchase. But how does the government or your condo board decide which public goods to spend its limited resources on? And how do these powers decide the best way to share the costs?

"In order to make the decision optimally and fairly," says Rangel, "a group needs to know how much everybody is willing to pay for the public good. This information is needed to know if the public good should be purchased and, in an ideal arrangement, how to split the costs in a fair way."

In such an ideal arrangement, someone who swims every day should be willing to pay more for a pool than someone who hardly ever swims. Likewise, someone who has kids in public school should have more of her taxes put toward education.

But providing public goods optimally and fairly is difficult, Rangel notes, because the group leadership doesn't have the necessary information. And when people are asked how much they value a particular public good—with that value measured in terms of how many of their own tax dollars, for instance, they’d be willing to put into it—their tendency is to lowball.

Why? “People can enjoy the good even if they don’t pay for it,” explains Rangel. "Underreporting its value to you will have a small effect on the final decision by the group on whether to buy the good, but it can have a large effect on how much you pay for it."

In other words, he says, “There’s an incentive for you to lie about how much the good is worth to you.”

That incentive to lie is at the heart of the free-rider problem, a fundamental quandary in economics, political science, law, and sociology. It's a problem that professionals in these fields have long assumed has no solution that is both efficient and fair.

In fact, for decades it's been assumed that there is no way to give people an incentive to be honest about the value they place on public goods while maintaining the fairness of the arrangement.

“But this result assumed that the group's leadership does not have direct information about people's valuations,” says Rangel. “That's something that neurotechnology has now made feasible.”

And so Rangel, along with Caltech graduate student Ian Krajbich and their colleagues, set out to apply neurotechnology to the public-goods problem.

In their series of experiments, the scientists tried to determine whether functional magnetic resonance imaging (fMRI) could allow them to construct informative measures of the value a person assigns to one or another public good. Once they’d determined that fMRI images—analyzed using pattern-classification techniques—can confer at least some information (albeit "noisy" and imprecise) about what a person values, they went on to test whether that information could help them solve the free-rider problem.

They did this by setting up a classic economic experiment, in which subjects would be rewarded (paid) based on the values they were assigned for an abstract public good.

As part of this experiment, volunteers were divided up into groups. “The entire group had to decide whether or not to spend their money purchasing a good from us,” Rangel explains. “The good would cost a fixed amount of money to the group, but everybody would have a different benefit from it.”