These studies are all American and, therefore, not explicitly indicative of the Canadian situation. But obviously worth consideration.
Going Negative. “Our experiments, and corroborating evidence from actual Senate election results, reveal that high-tech advertising campaigns can stimulate people to vote and instill a sense of confidence in government, but only through positive campaign messages.”
Demobilizer or Mobilizer. “We must conclude that attack advertising’s demobilization dangers are greatly exaggerated by Ansolabehere et al., while they completely miss negative political advertising’s turnout benefits — at least in voters’ own context.”
Understanding the effects of political advertising. “Advertising can and sometimes does have a positive effect on voter turnout, but by no means is that effect large, universal, or consistent across election years. On the other hand, there is very little evidence that advertising, whatever its other effects, has any negative effect on voter participation in America.”
The influence of negative advertising. “Results demonstrated that participants were more likely to generate cynical comments and hold politicians accountable for the country’s ills when reading candidate theme advertisements than ad hoc issue advertisements. The results indicate that this contributes to a political climate of cynicism and may function to erode the electorate’s overall trust in government.”