Using Experiments to Estimate Racially Polarized Voting

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Principal investigator:

Marisa Abrajano

University of California, San Diego



Sample size: 1617

Field period: 09/21/2015-08/25/2016


Does treatment mode matter in studies of the effects of candidate race or ethnicity on voting decisions? The assumption implicit in most such work is that such treatment mode differences are either small and/or theoretically well understood, so that the choice of how to signal the race of a candidate is largely one of convenience. But this assumption remains untested. Using a nationally representative sample of white voting age citizens and a modied conjoint design, we evaluate whether signaling candidate ethnicity with ethnic labels and names results in different effects than signaling candidate ethnicity with ethnically identifiable photos and names. Our results provide strong evidence that treatment mode effects are substantively large and statistically significant. Further, these treatment mode effects are not consistent with extant theoretical accounts. These results highlight the need for additional theoretical and empirical work on race/ethnicity treatment mode effects.


Hypothesis/Research Questions:

We hypothesized that the candidates depicted as Latino would receive less voter support when race/ethnicity was communicated using photographs as opposed to written labels, and we expected the differential treatment to be most pronounced among respondents who, by standard social- psychology metrics, are "internally motivated to control stereotyping" (Plant and Devine, 1998).

Experimental Manipulations

We vary the way ethnicity of the candidate is conveyed, either via a photo or a written label (e.g. Latino, White).

Outcome Variables:

vote choice

Summary of Results

Contrary to our main hypothesis, our findings reveal that white respondents who are internally motivated to control stereotyping gave almost exactly the same vote share to Latino candidates in the "labels" and "pictures" branches of our study. Yet respondents who are not so motivated chose the white candidate by landslide margins in the labels condition, while giving only slightly more support to white candidates than Latino candidates in the pictures condition. Overall, Latino candidates fared significantly worse when their ethnic identity was conveyed via labels rather than pictures. These findings conrm that treatment-mode differences do exist where the focal attribute is race/ethnicity, and reinforce the need for additional research on the subject matter.


Labels vs. Pictures: Treatment-Mode Effects in Experiments About Discrimination, Political Analysis, Forthcoming