Todd Donovan, Caroline Tolbert, and Kellen Gracey have written this article for Electoral Studies. Here is the abstract:
We present reasons to expect that campaigns are less negative under preferential voting. We then examine if preferential voting systems affect how people perceive the conduct of elections. This paper reports results from surveys designed to measure voters‘ perceptions of candidates’ campaigns, comparing places with plurality elections to those that used preferential voting rules. Our surveys of voters indicate that people in cities using preferential voting were significantly more satisfied with the conduct of local campaigns than people in similar cities with plurality elections. People in cities with preferential voting were also less likely to view campaigns as negative, and less likely to respond that candidates were frequently criticizing each other. Results are consistent across a series of robustness checks.