Heavy advertising by both Democratic and Republican presidential candidates during the 2008 election may actually make voters in battleground states more confused about which candidate to vote for, a new study suggests. 

A nationwide study found that voters in heavily contested states like Florida and Ohio become more ambivalent when they are exposed to a lot of opposing messages from the two candidates.

"In battleground states especially, both candidates will invest a lot of money in television commercials. So people in these states are getting a lot of competing messages from both candidates and that translates into voters in these states wrestling with conflicting ideas," said Luke Keele, co-author of the study and assistant professor of political science at Ohio State University. 

The total volume of candidate ads in a state had no effect on ambivalence levels among residents. However, ambivalence levels were higher in states where there was a high number of Democratic ads and a high number of Republican ads running at the same time.

"But if you live in a state that is not competitive, you're probably seeing one-sided messages from a single candidate or few messages at all, so you're less likely to be ambivalent. So the state in which you live can influence your decisions." 

The results appear in the October 2008 issue of the journal Political Psychology.

The study was based on survey responses from the 2000 edition of the American National Election Study, a nationally representative survey of voters that examined the race between George Bush and Al Gore, as well as U.S. House of Representatives' races. The survey, which is performed every two years by the University of Michigan, included face-to-face interviews with more than 1,800 people. 

Keele and Jennifer Wolak, assistant professor of political science at the University of Colorado, Boulder, used responses from the survey to measure differences in ambivalence levels between people in different states. Respondents living in highly competitive states were matched with people with similar political, social and economic characteristics living in non-battleground states. 

To measure the level of ambivalence, the researchers looked at the number of positive and/or negative items that respondents listed about both presidential candidates. Respondents who listed negative items about both candidates, or positive items about both candidates, would be rated as more ambivalent. Those who listed positive items about just one candidate, or negative items about just one contender, would be rated as less ambivalent.

In addition, the researchers examined the total amount of television advertising spending in each state by the two candidates and the Democratic and Republican parties in the 2008 election.

The results showed that the total volume of candidate ads in a state had no effect on ambivalence levels among residents. However, ambivalence levels were higher in states where there was a high number of Democratic ads and a high number of Republican ads running at the same time.

"Competition in presidential ad spending promotes ambivalence," Keele said. "People are continually hit with conflicting messages."

But the results show that it's not just the advertising that can promote ambivalence among voters. Voters can become confused whenever they consistently hear conflicting messages about the candidates.

For example, people living in states with a balance between Democrats and Republicans were more uncertain about presidential candidates than were those in states where one political party dominated. This type of environment leads to greater discussion of issues and candidates and even greater exposure to opposing viewpoints, Keele said. 

Likewise, discussing politics with people who favored the same presidential candidate decreased ambivalence for many voters. In contrast, people were more ambivalent when they discussed politics with others who favored the opposing candidate. These ambivalent voters were more likely to internalize competing arguments from their colleagues and friends, affecting their confidence in candidates overall, he said. 

"If you live in a place where everyone thinks the same way in partisan terms, the chance that you're going to question your ideas is quite a bit lower. If all your neighbors have John McCain signs and everyone you talk to is moving in the same direction in terms of a candidate, you are probably not going to waver too much if you were on the edge in the beginning," Keele said. 

But the study also found that the dynamics between political ads and ambivalence was different in races for the U.S. House of Representatives than it was for the presidential race. Political advertising by a House candidate decreased ambivalence about that candidate and increased ambivalence about the opponent. 

"A lot of the congressional races aren't very competitive. So you get an incumbent running against someone who really has no chance and voters don't get as many competing messages," he said. 

While advertising and other aspects of the political environment influenced levels of ambivalence among presidential voters, Keele emphasized that personal characteristics, such as party identification and education, are still very influential in predicting ambivalence. 

For example, those with college degrees were more likely to be ambivalent than those with only a high school education. Keele said this factor may be tied an individual's level of political knowledge. 

"Those with higher education tend to watch debates, they read the newspaper, and they hear more of the competing sides. Then there are others who are tuning out politics by not watching the news or paying attention to TV commercials, and there is just very little awareness of competing viewpoints. So since there is very little awareness, they're less ambivalent," he said. 

The results also showed that those with strong partisan ties were much less likely than independent voters to be ambivalent. And this factor was much more important in explaining ambivalence than whether a person lived in a battleground state or not. 

"A lot of partisans have made up their mind by the time the conventions are over, if not before," Keele said. "But there are some people out there who will be more affected by events, by television commercials, by neighbors, and by campaign strategies. And they are the ones who are more likely to remain undecided longer."