The survey was designed using the online application Qualtrics, and administered to an online panel of nationwide U.S. respondents. Online panels are comprised of individuals who contract with an organization or corporate entity (in this case, Qualtrics, LLC) to complete surveys for research, marketing, or other analytics purposes, in return for compensation. The survey was administered by a designated management team at Qualtrics, LLC. The sampling procedure was stratified to capture a roughly even admixture of self-identified liberals and conservatives. Panelists were emailed a link to a new survey. If they followed the link, they were directed to the first page of the survey, which asked for consent to participate in a research study. By proceeding to the next page respondents signified their consent. Once the targeted sample size had been achieved, the survey was closed to additional respondents.
To measure donation we employed a procedure documented by Clements et al. (2015). Respondents were told they would receive $5, in addition to their normal panelist earnings, and were offered the opportunity to designate some proportion of the $5 as a donation. After choosing to donate (or not), respondents viewed a de-debrief page informing them that their donations had been recorded as data, a detail that had been withheld from the initial consent document so as to render the donation decision context as naturalistic as possible. Because of the minor deception, in accordance with standards stipulated by the Oregon State University Institutional Review Board, respondents were offered the opportunity to withdraw their data from the sample without forfeiting payments owed to them. Data from respondents who chose to withdraw (N = 269) are not included in the dataset. Upon completion respondents were thanked for their participation and payment was issued according to their contracted arrangement with Qualtrics, LLC. The research team calculated additional payments owed to respondents from the donation incentive (see “experimental design”), and these payments were issued to panelists by Qualtrics, LLC.