The night the Republican presidential candidates debated in Houston, 50 Iowa voters sat wired to a "Perception Analyzer" in Des Moines. It may have been the harbinger of a promising new technology or, as one political scientist put it, "the most egregious insult to democracy that I've seen in the 200th anniversary of the Constitution."

Assembled in a hotel meeting room by operatives of Vice President Bush, the recruits were paid $25 each to watch the debate on television and react positively or negatively by turning a dial. Each hand-held Perception Analyzer was hooked into a microprocessor that produced a zig-zagging computer display recording everyone's "instantaneous output" and affixing a digital value to each crest and trough.

"Bush went through the ceiling when he stressed that his loyalty is not a character flaw," recalled his deputy campaign manager Rich Bond, who sat in on the Oct. 28 session to watch the zigs and zags. "And {former Delaware governor Pierre S.} du Pont went through the floor with his attack on Bush. He never got back in the ballgame after that. {Sen. Robert J.} Dole did fair. {Former secretary of state Alexander M.} Haig was always just kind of in the middle zone . . . . "

"It's a good way to find out how people react to various parts of a long program," Bush pollster Robert L. Teeter said. "There isn't any kind of feelly or touchy business to it. It's a very specific kind of research technique that's useful but limited."

The Perception Analyzer, the brainchild of Columbia Information Systems of Portland, Ore., signals the increasing political application of a method that was originally developed in the 1930s for the business world. The first such device, invented by sociologist Paul Lazarsfeld and CBS research director Frank Stanton, was a primitive box outfitted with push buttons to measure the programming preferences of radio listeners.

Today, the technology is much refined -- portable, quick, adaptable and computerized. Similar devices have been used occasionally in the last three presidential campaigns but never so much as now.

Among the gadgets are the "electronic response system," employed last July by a Seattle firm to measure audience response to the first Democratic debate, the "Tell-Back" system from a company in Spokane and "Ballot Box" from a Greenwich, Conn., firm.

"Back in the days of Lincoln and Douglas, their debates were in front of an audience, and they could see how they were going over and modify their performance," said Professor G. Ray Funkhouser of the University of Pennsylvania's Annenberg School of Communications. "But with mass communications, the problem is that the feedback is indirect and delayed. You're really addressing millions of people you can't see."

Now, that problem is solved, proponents of the technology say.

"It gives candidates an idea of what kinds of phrases, intonations and body language convey a favorable impression," said Greg Markus, a professor at the University of Michigan's Center for Political Studies.

"It enables the speaker, if he's got a healthy ego, to close a lot of the loop between himself and the people he's talking to," said John Fiedler of Populus Inc., which markets the Ballot Box system. "It's an overall emotional reaction -- not terribly cognitive, not terribly rational, to what people are seeing and hearing," said Fiedler, who directed media and communications research for President Reagan's reelection campaign.

Not that everyone thinks the technology is so promising.

"Democracy is meant to be government by consent of the governed, not government by consent of their guts," said Duke University political scientist James David Barber. "It's a prime illustration of the deterioration of political discourse in this country, the substitution of sentiment for reason."

One of the advantages of the Perception Analyzer, according to its promotional material, is that "it allows us to avoid the problems of semantic ambiguity and limited communication skills" so often encountered in focus groups, where participants are called upon to speak.

Columbia Information Systems supervised the Bush gathering in Iowa -- the site of next February's opening presidential caucuses -- and held simultaneous sessions in Atlanta and Portland. The sessions, said company president Michael Malone, constituted "the shakedown run" for what will soon become "Debate Watch," a service offering political campaigns and media organizations, at $6,000 a crack, the instant judgments of 400 randomly selected dial-twisters in eight cities at once.

In the meantime, the competitive scramble is on. Thomas L. Westbrook, president of Tell-Back Inc., hopes to offer a similar service, while Christopher Wheeler, whose company monitored the Democratic debate, is positioning himself to sell his wares to one of the Democratic candidates, probably Sen. Paul Simon (Ill.).

"We're watching how the ranks are forming, seeing who's performing well or not so well, and on the basis of that we're aligning ourselves with a candidate," Wheeler said. Dole pollster Richard Wirthlin, a former associate of Fiedler, replied "I'm sure we will," when asked if the Dole campaign plans to use Ballot Box.

"It ends up being kind of an arms race," Markus said. "Somebody's using this, so everybody else has got to use it."

The Bush campaign paid about $9,000 for the session in Des Moines and was unwilling to characterize the results or describe the composition of its group, although Malone said it included uncommitted Republicans. But data from the Portland session -- whose 45 participants were avowed conservatives by 2 to 1 over moderates, with a similar ratio of men to women -- suggested that the vice president also performed respectably with a mostly conservative crowd.

"Bush held his own across the board," said Malone. "Dole did very poorly. His support was cut in half. DuPont and Haig seemed to pick up what Dole lost. {Rep. Jack} Kemp and {former television exangelist Marion (G.) Pat} Robertson basically stayed about the same. Robertson, because of the strong conservative base here, did atypically well."

Malone said follow-up interviews, conducted a week after the debate, showed that these initial postdebate reactions stuck.

As for the Bush campaign, while Bond sat watching in Des Moines, television consultant Roger Ailes was holed up in the vice president's holding room in Houston -- not giving the Perception Analyzer a second's thought, he said.

"I still don't know how the graph works and I don't care," Ailes insisted. "I believe that technology is useful up to a point. But when I make a commercial, I don't paint by the numbers. I once asked a great jazz saxophonist if he read music. And he said, 'Sure, but only as much as it doesn't hurt my playing.' "