Attack ads actually stimulate voting

[Stone Island]

Goldstein, Ken and Paul Freedman, "Campaign Advertising and Voter Turnout: New Evidence for a Stimulation Effect" in The Journal of Politics, Vol. 64, No. 3 (Aug., 2002), pp. 721-740.

...there is good reason to expect vigorous campaign attacks to stimulate voters: by engaging voters, by raising interest, and by communicating the notion that something important is at stake in the outcome of an election, negative ads (whether they are "contrast" ads or "pure negative" spots) should be more likely to stimulate than depress voter turnout.