Japanese researchers have shed more light on the psychology of why we care about economic inequality: Using mouse-tracking data from people choosing between options for distributing money virtually to others, they showed that people care less about equalizing resources overall than about helping the neediest.

"Often, debates about resource allocation are framed as a choice between maximizing the total amount of resources — increasing efficiency — and minimizing the variance in the outcome — prioritizing equality," Tatsuya Kameda, a psychologist at the University of Tokyo and an author of the paper, told The Academic Times. "Do people really mean to reduce variance when they endorse the notion of equality? Or do they actually care about the worst-off possibility when saying 'equality is the key'? We showed that what many people actually mean by 'equality' is better captured by the latter concern about the worst-off case, rather than the concern about the variance per se."

In the study, published Tuesday in Royal Society Open Science, 36 participants answered a total of 48 choice problems on a computer monitor, with researchers tracking moment-to-moment mouse activity. In every problem, the participants had to decide between a pair of choices for distributing money. Each choice, they were told, would impact three actual people: Person A, who got the least money; Person B, who got a medium amount of money; and Person C, who got the most money. 

Every problem was designed so that one of the choices was more efficient, meaning it yielded more money overall, while the other choice was both more egalitarian and best for the poorest — in other words, there was less of a difference between Person A and Person C, and Person A got more money. Each choice also included data on "variance," which participants were told reflected the distribution's overall equality.

Participants were much less likely to choose the more efficient "utilitarian" option. Additionally, the mouse-tracking data revealed that they were much more attentive to the worst-off person, Person A, than they were to the variance. This minimum value influenced the cursor's position at some of the earliest stages of decision-making, just 500 milliseconds after the problem appeared on participants' computer screens.

Kameda agrees that this concern with the worst-off could be equated with the "floor" that a society creates for the neediest. In earlier neuroimaging research, he found that people cared most about the worst possible outcome when making decisions, either for themselves or for other people.

"We conjecture that when making choices, people first spontaneously and naturally engage in imagining, 'What if the worst case may happen,'" Kameda explained. "I think that this spontaneous cognitive focus on the worst possibility serves us — humans as well as animals — to survive in an uncertain natural environment."

Kameda believes his research supports the work of philosopher John Rawls. In his famous "original position" thought experiment, Rawls imagined how people would distribute resources within a society from behind a "veil of ignorance," which would prevent them from knowing how much they themselves received. He claimed they would give as much as they could to the worst-off person. This "maximin" principle sparked a controversy that rages to this day.

Since Rawls wrote in the 1970s, researchers have found ways to test his theory. In 1992, Norman Frolich and Joe. A. Oppenheimer published a book-length investigation of Rawls' maximin principle, finding little support for it among the people they interviewed. Yet in an influential 2004 paper, Dirk Engelmann and Martin Strobel found that maximin preferences seemed to guide participants in a series of distribution tests.

Given the health risks and other dangers of inequality, it is crucial to understand how and why people object to it — or, in this case, why inequality may be less simple than it appears. Fortunately, open democratic debate may be a solution. In another recent study, Kameda and his coauthors found that social deliberation led people to focus less on equality and more on the well-being of the poorest.

The team believes their mouse-tracking results can best be explained by participants' judgments about equality or the lowest floor. Yet they recognize the limitations of their research: all of the participants were students at the University of Tokyo, meaning that cultural factors could skew the researchers' findings. In addition, they acknowledged that participants made fairly abstract decisions in their experiments. Real-world choices might look different, especially if these participants did not believe that their payouts were going to actual people — the study did not incorporate any belief checks.

Kameda thinks this research can be applied to policy — more specifically, to how officials pitch new programs to their constituents. "When presenting a distributive policy to the public, framing the policy in terms of tradeoff between minimum and efficiency is more useful than as the tradeoff between variance and efficiency," Kameda said. He hopes his insights lead to effective nudges, which would use our concern for the worst off to help us choose broadly beneficial policies.

If these researchers are right, the supposed conflict between equality and economic efficiency may not be as irreconcilable as it may seem. The poorest could be served without significantly shrinking the overall pie.

"We believe that understanding the cognitive determinants of resource allocation decisions is critical toward the creation of contexts in which people find it easier to reach agreements about resource allocation," Kameda said.

The paper, "Reducing variance or helping the poorest? A mouse tracking approach to investigate cognitive bases of inequality aversion in resource allocation," published on March 16 in Royal Society Open Science, was authored by Atsushi Ueshima, the University of Tokyo and the Japan Society for the Promotion of Science; and Tatsuya Kameda, the University of Tokyo, Hokkaido University, and Tamagawa University.