Re-Ranking News Comments by Constructiveness and Curiosity Significantly Increases Perceived Respect, Trustworthiness, and Interest

Online commenting platforms have commonly developed systems to address online harms by removing and down-ranking content. An alternative, under-explored approach is to focus on up-ranking content to proactively prioritize prosocial commentary and set better conversational norms. We present a study with 460 English-speaking US-based news readers to understand the effects of re-ranking comments by constructiveness, curiosity, and personal stories on a variety of outcomes related to willingness to participate and engage, as well as perceived credibility and polarization in a comment section. In our rich-media survey experiment, participants across these four ranking conditions and a control group reviewed prototypes of comment sections of a Politics op-ed and Dining article. We found that outcomes varied significantly by article type. Up-ranking curiosity and constructiveness improved a number of measures for the Politics article, including perceived \textit{Respect}, \textit{Trustworthiness}, and \textit{Interestingness} of the comment section. Constructiveness also increased perceptions that the comments were favorable to Republicans, with no condition worsening perceptions of partisans. Additionally, in the Dining article, personal stories and constructiveness rankings significantly improved the perceived informativeness of the comments. Overall, these findings indicate that incorporating prosocial qualities of speech into ranking could be a promising approach to promote healthier, less polarized dialogue in online comment sections.