Regardless of the results of Tuesday's primary election in Pennsylvania, when the polls close, most voters will be pleased with the pause from all those negative campaign ads.

Not sharing that sentiment, however, is David Redlawsk, professor of political science at Rutgers University and director of the Eagleton Center for Public Interest Polling.

While voters dislike certain kinds of negative campaigning, Redlawsk said, they actually find other types useful.

"They're not especially upset about negativity that provides information on issues, that talks about an opponent's experience, or that contrasts the candidate and the opponent," he said. "However, they dislike ads that attack on a personal level -- things we would call mudslinging."

Redlawsk has elaborated on his research in a new book, "The Positive Case for Negative Campaigning," with co-author Kyle Mattes. He spoke with NewsWorks Tonight's Dave Heller.