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Harvard researchers find that only men showed favoritism toward supporters of their preferred candidate

in the 2008 Democratic primary

Cambridge, Mass. - Men, but not women, displayed strong favoritism toward fellow supporters of Hillary Clinton or Barack Obama during the summer of 2008, according to a new study published in the Proceedings of the National Academy of Sciences by researchers at Harvard University.

“While the popular perception was that women were driving much of the strife in the Democratic party after Clinton’s defeat – the so-called ‘P.U.M.A’ movement – that was not what we found,” said David G. Rand of the Program for Evolutionary Dynamics. “Even older female supporters of Hillary Clinton did not discriminate against Obama supporters.”

The group of researchers, led by Rand and Yochai Benkler of the Berkman Center for Internet and Society, investigated in-group favoritism among 395 Democrats from Cambridge, MA. Subjects participated in the “dictator game,” a test of generosity developed by behavioral economists. Each participant was given $6 and asked to divide the money between himself or herself and another anonymous supporter of one of the two candidates.

Men were more generous toward supporters of their own preferred candidate than to supporters of the other Democratic candidate, the study showed. Women, on the other hand, gave the same amount regardless of which candidate the recipient supported.

The researchers also observed a change in the attitudes of the men as events unfolded in the campaign. Male Democrats showed in-group bias immediately following Clinton’s concession in June, and this bias persisted until the end of the Democratic National Convention (“DNC”). Immediately following the DNC, party unity was restored, and the men donated the same amount to supporters of either Clinton or Obama.

“It was particularly interesting to see that it was not the fact that the internal conflicts were over that created the change, or that there was now a common adversary. These alone were not enough to get people to overcome their in-group bias,” said Benkler. “Instead, it was the public performance of reconciliation that seemed to have an immediate effect.”

The study also uncovered a difference in the level of bias shown by Obama and Clinton supporters. Supporters of Clinton discriminated more against Obama supporters than the other way around. “Hillary Clinton’s supporters were upset about her defeat in the primary, and this may have led to stronger feelings of hostility,” Rand said. “However, our findings have a positive message: even when deep resentment and in-group bias exist, reconciliation is possible. Symbolic displays of unity like those that occurred at the DNC can bring people back together, as further evidenced by Obama’s victory in the general election.”

The study, Dynamic remodeling of in-group bias during the 2008 presidential election, was supported by the Kauffman Foundation and the Society in Science/The Branco Weiss Fellowship. It was published online in PNAS Early Edition this week, and will appear in print within the next month.

David G. Rand
Program for Evolutionary Dynamics

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