With the political divide seemingly wider than ever, you'd think the sight of another political ad would set Americans' blood boiling. But that doesn't seem to be the case. Instead, when people see advertisements for politicians they don't like, they don't get angry, they just ignore them.

While advertisements for politicians the viewer supports help to intensify their feelings of support, ads for politicians the viewer does not support do not have the opposite effect. Instead, the viewer just tunes the ads out.

That's the finding of researchers who have determined that people have almost no physical reaction when they see political advertisements with which they disagree. To study how people react to political ads, researchers study the heart rate, skin conductance (sweating) and muscle movement in the cheek and eyebrows of study participants. These factors were measured to determine participants' physical reaction to political advertisements for candidates they didn't support.

"A lot of research has shown that, behaviorally, we tend to selectively expose ourselves to information that reinforces our existing opinions. But this study further suggests that even when exposed to information, our attention to what is presented is highly selective, as well," Zheng Wang, lead author of the study and assistant professor of communication at Ohio State University.

The researchers observed that when participants watched political ads with which they disagreed, their heart rates were lowered. This suggests a lack of interest in ads, the researchers said. Additionally, they found that respondents had little muscle movement in their faces, which may signal they were not paying attention to ads.

"At any one time, ad viewers' reactions are affected not just by what they are seeing at that exact moment, but also by what came before in the ad," Wang said. "The dynamical feedback model puts it all together to see how people react in a real-time, real-world way. The ad message is only part of the story because it interacts with how individuals process the advertisement. When we integrate all of the ad message inputs into this dynamical system of the viewer’s mind, we find the response of supporters is intensified, while the opponents become nonresponsive."

Although this research was based on responses to political advertisements, it highlights an area of concern for all advertisers. Particularly, it brings into question the reactions people have to ads for companies that they dislike.

The research was based on a study of 15 college students studied by Wang during the last presidential election. The study was partially supported by a grant from the National Science Foundation.

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This story was originally written for BusinessNewsDaily and is reprinted with permission here. Copyright 2012 BusinessNewsDaily, a TechMediaNetwork company.