Thanks to a high-tech device called the Perception Analyzer, this wasn't a fruitless exercise by a bunch of political couch potatoes. This group of undecided voters' opinions were recorded every second of the 90-minute debate.

The result?

A major win for Democrat Barack Obama. Seventy-one percent of these undecided voters thought Obama did better in addressing the issues important to them, while only 9 percent felt that way about Republican John McCain.

The group slightly favored Obama coming into the debate, but afterward he won support by about a 2-to-1 ratio.

"I think he talked about what they cared about more, especially the economy and health care," said Republican pollster Brenda Wigger, vice president of Voter/Consumer Research.

She and another national pollster, Democrat Celinda Lake, president of Lake Research Partners, watched the results in a room across the hall. Constantly moving horizontal lines showing the live "ratings" were superimposed on top of the TV debate broadcast in the other room.

Each voter was given a wireless dial -- dubbed a "feeling thermometer" -- to evaluate continuously the candidates, ranging from 0 (not convincing at all) to 50 (neutral) to 100 (very convincing). The devices are the same ones used in market research and to test TV pilots.

One of the most striking findings of the evening: The undecided voters displayed an open distaste whenever the candidates' rhetoric turned negative.

The dials turned to virtually their lowest point of the evening when McCain criticized Obama for not condemning U.S. Rep. John Lewis' comparison of McCain and running mate Sarah Palin's campaign rallies to the era of one-time segregationist Gov. George Wallace of Alabama.

And when McCain challenged Obama on the Illinois senator's connections with former Weather Underground leader William Ayers and the group ACORN (Association of Community Organizations for Reform Now), the voters' ratings barely budged above 50.

When Obama tried to explain himself on both matters, the dials hardly hit 60.

"This is all inside baseball to people," Lake said as she watched the ratings roll across the screen. "They want to see what are you going to do about my life, not William Ayers."

On the other hand, when Obama talked about his desire to find common ground on the issue of abortion, the dials shot up to more than 80.

McCain's ratings peaked when he talked about health care and stressed the need for energy independence and offshore drilling.

Initially, only women were chosen for the dial group because they were perceived to be more interested in health-care issues, Wigger said. But the selection of an all-female audience wound up providing an inside look at a key group of swing voters.

"Women are the ones moving the polls," Wigger said. "Women just tend to vote their heart rather than on a party."

The debate-watching event was organized by the Partnership to Fight Chronic Disease, which describes itself as a national coalition of more than 110 patient, provider and community organizations, business and labor groups, and health policy experts committed to raising awareness of rising rates of preventable and treatable chronic diseases.

Participants were paid $100 apiece to take part.

drowland@dispatch.com