Demonstrating racial bias is not easy -- as I've discussed before, nobody actually calls themselves racists, because much racial bias happens at the subconscious level -- so the USC researchers developed a novel real-world field experiment to test bias among state legislators. In the two weeks prior to the 2012 election, they sent e-mail correspondence to a total of 1,871 state legislators in 14 states. The e-mails read as follows:
Hello (Representative/Senator NAME),
My name is (voter NAME) and I have heard a lot in the news lately about identification being required at the polls. I do not have a driver’s license. Can I still vote in November? Thank you for your help.
The key to the experiment lies in that voter name field. One group of legislators received e-mail from a voter who identified himself as "Jacob Smith." The other received email from "Santiago Rodriguez." Moreover, half of the legislators in each of these two groups received e-mails written in Spanish, while half received English-language e-mails.
The researchers then measured the lawmakers' response rates to these e-mails. Crucially, in each state in the study, legislators really could have simply responded with a "yes" -- drivers' licenses were not required in any of the states in order to vote.
The researchers found that legislators who had supported voter ID laws were much more likely to respond to "Jacob Smith" than to "Santiago Rodriguez." This gap reveals a preference for responding to constituents with Anglophone names over constituents with Hispanic ones.
There was also an Anglophone preference among legislators who had not backed ID requirements, but crucially this preference was much smaller. This finding held true among legislators who received English-language e-mails, as well as legislators who received Spanish e-mails.
File under "N" for "No poo, Sherlock"