In a new paper, Broockman et al. use a clever manipulation to induce “three decades of change in affective polarization”:
In typical trust games, there are two players. Player 1 receives a cash allocation and is instructed to give “some, all, or none” of the money to Player 2. The player is also told that the researchers will triple any amount Player  gives to Player 2 and that Player 2 can return some, all, or none of the money back to Player 1. Therefore, the more Player 1 expects reciprocity from Player 2, the more money they should allocate to Player 2 in anticipation they will receive a larger sum in return, and the better off Player 2 will be. For example, if Player 1 gives all her money to Player 2, this sum would be tripled, and Player 2 could return half of the tripled amount to Player 1—leaving both players with 50% more than Player 1’s initial allocation. But if Player 1 gives no money to Player 2, Player 1 leaves with only her initial allocation and Player 2 leaves with nothing.
First, we always make participants take the role of Player 2. This means they always first observe an allocation another player makes to them. Second, across three consecutive rounds of game play, participants are told they are interacting with three other respondents of the opposite political party who have each been allocated $10. However, they are in fact are interacting with computerized opponents who offer allocations based on a pre-determined script. Participants randomized to the Positive Experience condition receive allocations from Player 1 of $8, $7 and $8 (tripled to $24, $21 and $24) respectively across the three rounds of the game. However, those in the Negative Experience condition receive $0 allocations in all three rounds.Broockman et al. 2021
Next, comes the punchline. “Player 1’s reason for their allocation to you: your partisanship (all rounds), your income (Round 2)”. See Page 65.
Being told that a co- or opposing- partisan gave $0 versus being told that they gave $8, $7, and $8 because of your partisanship across three rounds has a dramatic effect on partisans’ feelings: partisans’ feelings toward opposing partisans become ‘cooler,’ it doesn’t affect their feelings towards co-partisans (impressive), and (strangely) polarizes their feelings toward elites (see the figure below).
Three comments are in order.
First, the manipulation is unrealistic given previous effect sizes (see here).“The average amount allocated to copartisans in the trust game was $4.58 (95% confidence interval [4.33, 4.83]), representing a “bonus” of some 10% over the average allocation of $4.17.”
Second, the manipulation principally ought to change perceptions of how trusting people are and not how trustworthy they are. We don’t manipulate how deceitful the other person is but how fearful they are of not having their actions reciprocated. Disliking less trusting people is slightly weird and plausibly points to how the underlying antipathy can be exacerbated by treatments that do not present a clear reason for judging another person more harshly. Or it could be that not being seen as being trustworthy and losing out on money as a result of it is insulting and aggravating.
Whatever the reason, generalizing from a bad personal interaction to all other members of a group is disturbing. (The fact that treatment cools people’s feelings toward opposing partisans suggests people expect better from them, which is interesting.) Ascribing feelings from a bad personal experience to elites seems odder (and more disturbing) still.
The paper finds that having a “bad” personal experience (vis-a-vis a better one) with an opposing partisan increases interpersonal animus (plus polarization of feelings toward partisan elites) but doesn’t cause partisans to like opposing partisan MCs less or co-partisan MCs more (though see above. Note that the pooled estimate for the opposing party is 1.5% or so—which is about what I would expect; it likely deserves another run at the bank). (I didn’t understand the change from co-partisan and opposing-partisan MCs to “own MCs” in the next analysis, so I am omitting that.) The paper discusses other DVs:
- Interest in expressing party-consistent issue preferences (no effect)
- Support for bi-partisan legislation (~ more in favor)
- Opposition to democratic norms (pooled index seems to move by d = .09 and is nearly sig. at conventional levels). (I make a special reference to the index because presumably it has the least measurement error and is least likely to show an idiosyncratic pattern given sample size. There is also a small point about how multiple comparison adjustments are made—plausibly they should account for measurement error.)
- Endorsement of partisan-congenial claims (Ds yes; Rs no)
The theorized path from bad personal experience with a co- (or opposing) partisan to opposition to democratic norms, etc., seems convoluted to me. So let’s unpack the theoretical underpinnings of the expectations. Interpersonal animus among partisans is an indicator of affective polarization. And the experiment successfully manipulates interpersonal animus. So what’s the issue? One escape hatch is that the concept is not uni-dimensional. Another is that any increase in interpersonal affect manifests in political consequences only over long periods as it causes people to watch different media, trust different things, etc.