10. IRV encourages civility and less negative campaigning
IRV tends to reduce negative campaigning, since candidates are concerned about alienating voters who could give them a second-preference vote that the candidate might need to win. A concern expressed by some is that IRV could "dumb-down" campaigns as candidates try to avoid taking controversial stands so as not to alienate potential second-choice transfers. Depending on the mix of candidates in a race, the Australian experience does indicate that candidates adjust their rhetoric so as to be considered as a second-choice by voters that are not their core supporters. Does this accommodation reflect civility or timidity on issues?
It seems unlikely that IRV would encourage candidates to shy away from taking strong positions that differentiate themselves from the field. With IRV, no candidate can win simply by being everyone’s second-choice. A candidate without enough first-choice votes gets eliminated under IRV rules and never gets to benefit from congenial transfers from unalienated voters. This suggests a strategy of trying to excite enough voters to give the candidate their first-choice votes while avoiding nasty campaign tactics that will sour supporters of other candidates: a campaign based on issues that make candidates stand out without the alienating impact of negative ads. Since candidates will not be expecting second-choice transfers from voters at the other end of the political spectrum, but rather from supporters of candidates nearer their own perspective, there is less reason to avoid taking clear stands on issues.
However, one of the factors that is cited by those who argue IRV reduces negative campaigning has little to do with appealing for second-choice votes. This argument is that negative campaigning is simply less effective in multi-candidate races. When there are only two credible candidates in a race, a smear ad campaign may not convince any voter to switch toward the originator of the negative campaign, yet still be successful. Negative ads are intended to 1) get voters to switch candidates and 2) dissuade the supporters of one’s opponent from even bothering to vote at all. This is done at the calculated cost of repugnance, turning other undecided voters against the nasty campaigner. Creating cynicism toward politicians generally, and reducing voter turnout (particularly by your opponent’s supporters) is a proven tactic. In a race with multiple candidates, supporters of the smeared candidate have other candidates to switch to other than the originator of the negative ads. So the cost of going negative may not be counterbalanced by an equal pick-up of switchers.