Let's start with a re-quote regarding the purpose and research design of the Filindra and Kaplan 2016 experiment:
To determine whether racial prejudice depresses white support for gun control, we designed a priming experiment which exposed respondents to pictures of blacks and whites drawn from the IAT. Results show that exposure to the prime suppressed support for gun control compared to the control, conditional upon a respondent's level of racial resentment (p. 255).
Under the guise of a cognitive test, we exposed 600 survey participants who self-identified as white to three pictures of the faces of black individuals and another three of white individuals (p. 261).
For predicting the two gun-related outcome variable scales for the experiment, Table 1 indicates in separate models that the treatment alone, the treatment and a measure of symbolic racism alone, and the interaction of the treatment and symbolic racism all reach statistical significance at at least p<0.10 with a two-tailed test.
But the outcome variable scales are built from a subset of measured gun-related items. Filindra and Kaplan 2016 reported an exploratory factor analysis used to select items for outcome variable scales: 7 of 13 policy items about guns and 8 of 9 belief items about guns were selected for inclusion in the scales. The dataset for the article uploaded to the Dataverse did not contain data for the omitted policy and belief items, so I requested these data from Dr. Filindra. I did not receive access to these data.
It's reasonable to use factor analysis to decide which items to include in a scale, but this permits researcher flexibility about whether to perform the factor analysis in the first place and, if so, about whether to place all items in a single factor analysis or to, as in Filindra and Kaplan 2016, separate the items into groups and conduct a factor analysis for each group.
But the main problem with the experiment is not the flexibility in building the outcome variable scales. The main problem is that the research design does not permit an inference of racial prejudice.
The Filindra and Kaplan 2016 experimental design of a control and a single treatment of the black/white photo combination permits at most only the inference of a "causal relationship between racial considerations and gun policy preferences among whites" (p. 263, emphasis added). However, Filindra and Kaplan 2016 also discussed the experiment as if the treatment had been only photos of blacks (p. 263):
Our priming experiment shows that mere short exposure to pictures of blacks can drive opposition to gun control.
The Filindra and Kaplan experimental design does not permit assigning the measured effect to the photos of blacks isolated from the photos of whites, so I'm not sure why peer reviewers would have permitted that claim, which appeared in exactly the same form on page 9 of Filindra and Kaplan's 2015 MPSA paper.
Filindra and Kaplan 2016 supplement the experiment with a correlational study using symbolic racism to predict the ANES gun control item. But, as other researchers and I have noted, there is an inferential problem using symbolic racism in correlational studies, because symbolic racism conflates racial prejudice and nonracial attitudes; for example, knowing only that a person believes that blacks should not receive special favors cannot tell us whether that person's belief is motivated by antiblack bias, nonracial opposition to special favors, or some combination of the two.
My article here provides a sense of how strong a residual post-statistical-control correlation between symbolic racism and an outcome variable must be before one can confidently claim that the correlation is tapping antiblack bias. To illustrate this, I used linear regression on the 2012 ANES Time Series Study data, weighted and limited to white respondents, to predict responses to the gun control item, which was coded on a standardized scale so that the lowest value is the response that the federal government should make it more difficult to buy a gun, the middle response is that the rules should be kept the same, and the highest value is that the federal government should make it easier to buy a gun.
The standardized symbolic racism scale produced a 0.068 (p=0.012) residual correlation with the standardized gun control item, with the model including the full set of statistical control as described in the note below. That was about the same residual correlation as for predicting a standardized scale measuring conservative attitudes toward women (0.108, p<0.001), about the same residual correlation as for predicting a standardized abortion scale (-0.087, p<0.001), and about the same residual correlation as for predicting a standardized item about whether people should be permitted to place Social Security payroll taxes into personal accounts (0.070, p=0.007).
So, based on these data alone, racial prejudice as measured with symbolic racism has about as much "effect" on attitudes about gun control as it does on attitudes about women, abortion, and private accounts for Social Security. I think it's unlikely that bias against blacks causes conservative attitudes toward women, so I don't think that the 2012 ANES data can resolve whether or the extent to which bias against blacks causes support for gun control.
I would bet that there is some connection between antiblack prejudice and gun control, but I wouldn't argue that Filindra and Kaplan 2016 provide convincing evidence of this. Of course, it looks like a version of the Filindra and Kaplan 2016 paper won a national award, so what do I know?
1. Code for my analysis reported above is here.
2. The full set of statistical control has controls for: respondent sex, marital status, age group, education level, household income, employment status, Republican party membership, Democratic Party membership, self-reported political ideology, and items measuring attitudes about whether jobs should be guaranteed, limited government, moral traditionalism, authoritarianism, and egalitarianism.
3. Filindra and Kaplan 2016 Table 2 reports a larger effect size for symbolic racism in the 2004 and 2008 ANES data than in the 2012 ANES data, with respective values for the maximum change in probability of support of -0.23, -0.25, and -0.16. The mean of the 2004 and 2008 estimate is 50% larger than the 2012 estimate, so increasing the 2012 residual correlation of 0.068 by 50% produces 0.102, which is still about the same residual correlation as for conservative attitudes about women. Based on Table 6 of my article, I would not be comfortable alleging an effect for racial bias with anything under a 0.15 residual correlation with a full set of statistical control.