Andrew Gelman wants to see the evidence for the effects of subliminal primes on policy attitudes; fair enough. A bit more Googling would have gotten him to Cengiz Erisen’s Stony Brook dissertation, “Affective Contagion: The Impact of Subtle Affective Cues in Political Thinking.” Chapter 3 reports a variety of analyses linking affective primes (happy or sad cartoon faces) to political attitudes and policy evaluations. Here’s an example (Figure 3.1) involving attitudes on illegal immigration.

In this case, subliminal exposure to a smiley cartoon face reduced negative thoughts about illegal immigration, increased positive thoughts about illegal immigration, and (crucially for Gelman) substantially shifted policy attitudes. The results for some of Erisen’s other cases are not as clear, and I haven’t signed up for “significantly and consistently alter,” as Gelman’s headline seems to imply. (It isn’t clear from his post where that quote comes from.) But I do think Erisen’s work provides some powerful evidence of the impact of irrelevant stimuli in political thinking.

One of the commenters on my previous post, Ulium, raises a different question, about the durability of these effects. Long-term evidence is, as s/he notes, in sadly short supply in experimental work. But I’m not sure why that should be reassuring for democracy. After all, the experimental evidence for the impact of considerations we would like to matter has the same limitation. Is there any reason to suppose that citizens generally succeed in forgetting the “irrelevant” stuff and remembering the “relevant” stuff?

In this case, according to Milton Lodge and Charles Taber, effects on policy attitudes were measured “up to 45 minutes” after the original subliminal primes. That’s something. Then, too, there is observational evidence along similar lines suggesting real political effects (for example, Andrew Healy, Neil Malhotra, and Cecilia Hyunjung Mo on college football games and election outcomes).

Do results of this sort warrant alarm? Gelman refers in his final paragraph to “concerns about democracy expressed by Bartels.” I’m not sure what “concerns about democracy” he detected. Just for the record, I’m okay with democracy. It’s unrealistic theories of democracy I object to.