Hsu Puts the Brain's Decision-Making Processes Under the fMRI Spotlight

Ming Hsu likes to present people with tough choices. For example:

Which of two coins - one that is perfectly balanced or one that has an unknown bias in favor of either heads or tails - would you pick to best enhance your chances in a coin flip? Your answer on this one most likely reflects how you also make certain investment decisions.

After looking at photos and reading biographies of children living at a real-life children's home in Africa you are asked to decide how to allocate food to them. Don't expect to feel entirely good about your charity, however. Hsu set up the experiment so test subjects have to choose between giving a set number of meals to one child or giving fewer meals, but to more children.

The coin question relates to what is called the Ellsberg Paradox, which has to do with aversion to ambiguity in decision-making, while the children's home dilemma came from an experiment Hsu ran while at Caltech using functional Magnetic Resonance Imaging (fMRI) to study how the brain functions during moral decision-making. As it turns out the odds in the coin flip are the same no matter which one you choose and the children's home gained a lump sum donation for food at study's end. What Hsu gained was insight into how the human brain works when asked to make difficult choices involving primal issues like risk/reward and morality.

Hsu's area of study is neuroeconomics, which is a combination of neuroscience and economics and a subset of behavioral economics. Hsu, who has a Ph.D. in Social Sciences from Caltech, is currently a Beckman Fellow and he will be joining the faculty of the Department of Economics at Illinois in the fall as an assistant professor.

"It's combining neuroscience and economics," Hsu said of his field. "Traditionally economics is formal models of decision-making, and some of it is from real-world data. Behavioral economics is sort of a fusion of psychology and economics, and neuroeconomics brings in neuroscience as well."

Neuroeconomics is a cutting edge field in a discipline, economics, with a history of being slow to adapt to new ideas (using fMRI techniques to study economic decisions is less than a decade old). Nevertheless, and not surprisingly, the idea of looking at the brain as it deliberates questions like how to distribute food to needy children or how to invest one's money has drawn a national spotlight. Hsu's work at Caltech has been written about in the Wall Street Journal and was featured in a recent episode of the PBS science show Curious, aired nationally on Jan. 24.

That show focused on the experiment run by Hsu and his colleagues at Caltech involving the Canaan's Children's Home in Uganda. Test subjects were put into a headscanning magnet and made donation decisions by pushing one of four colored buttons to move a ball on a screen to one of the donation options. Hsu calls it a distributive justice experiment.

"They have a decision whether to donate more money in total to the kids or to be more equitable in their distribution," Hsu said. "So you can imagine 'I can give 24 meals to one kid or 10 each to two.' In one case you are giving more in the sum and then the second case you are being more equitable and you are giving to more kids, but the total is less."

Hsu said they varied the donations so that there was a tension between being equitable and donating the largest amount possible to the children.

"We can vary these numbers to see what your aversion to inequity is and see what brain areas are responding to issues of equity and efficiency," he said.