Study 1 randomly assigned thousands of respondents to one, two, or three depolarization treatments.

Evidence

To assess the potential additive effects of multiple treatments, we recruited 3,525 respondents for our study. Prior to randomization, all participants completed an attention check to ensure data quality. Respondents were then randomly assigned to one of four conditions: a control group, which read a neutral vignette about sea otters (designed to match the average length of the substantive interventions), or one of three treatment groups, receiving either one, two, or three interventions. For the oneand twointervention conditions, treatments were randomly drawn from a set of three interventions from the MegaStudy detailed above. — Derek E. Holliday, Yphtach Lelkes, and Sean J. Westwood, Why Depolarization Is Hard, 53

Categorization

• QUESTION: The study stopped at three doses — did they test a ceiling, or could more than three stacking doses eventually move the needle?
• corroborated: 2 independent passages support this claim — Derek E. Holliday, Yphtach Lelkes, and Sean J. Westwood, Why Depolarization Is Hard: Evaluating…, 53