Experimental Design Details
Prior Elicitation
At the beginning of the experiment, we will elicit participants’ prior beliefs about Democrats’ and Republicans’ intelligence (or trustworthiness). Specifically, in the intelligence condition, they will be asked to estimate how many questions a randomly selected Democrat and a randomly picked Republican answered correctly in the cognitive test in our previous study. In the trustworthiness condition, they will be asked to estimate how much a randomly selected Democrat and a randomly picked Republican returned as the second-mover in a trust game. To provide a reference point, we will inform participants about the overall average performance across all partisans. This allows participants to focus on assessing whether Democrats and Republicans performed above or below the average, rather than making completely uninformed guesses.
Intervention
The treatment group in each condition will receive correct information about the average performances of Democrats and Republicans in the tasks. In contrast, participants in the control group will not receive any information.
Posterior Elicitation
We then elicit participants’ posterior beliefs to assess how much treated participants update their beliefs in response to the provided information, serving as a manipulation check. To minimize consistency bias and demand effects, we will use a different elicitation method from the prior belief, helping participants distinguish between the posterior and the prior. Specifically, we will frame the task as a prediction exercise, telling participants that we will invite more partisans to complete the cognitive test (or the trust game) and asking them to predict the performance of a randomly selected Democrat and a randomly selected Republican. Instead of providing a single estimate, participants will assign probabilities to different possible numbers of correct answers (or different possible return amounts). We will then calculate the mean of these probability-weighted expectations to construct their posterior belief.
Affective Polarization Measurement
We will ask participants about their feelings towards general Democrats and Republicans, and take the difference between co- vs counter-partisans.
Willingness to Accept (WTA) to Chat
To better understand the behavioral consequences of affective polarization, we also measure participants’ willingness to engage in a 10-minute anonymous online text chat with a randomly selected participant. Each participant is presented with three topic areas as potential conversation starters: (1) contentious political issues, (2) contentious pop culture issues, and (3) contentious personal finance strategies. These topics are chosen to vary in required levels of cognitive effort and mutual trust. Pop culture topics are expected to require lower levels of both, while political and finance topics are expected to require higher levels.
For each topic, participants indicate the minimum amount (between $0 and $10) they would accept to chat with a randomly selected Democrat and a randomly selected Republican. Responses are incentivized using the Becker-DeGroot-Marschak (BDM) method (Becker et al., 1964).
Before entering their responses, the computer pre-selects a random offer between $0 and $10. After participants submit their minimum acceptable amounts, one topic and one partisan identity (Democrat or Republican) are randomly selected. If the computer’s offer exceeds the participant’s stated minimum for that combination, the chat takes place and the participant receives the payment. If not, no chat occurs and no payment is given, and the study ends.