When $55-a-week composer Harold Arlen and lyricist Ted Koehler hit on a simple phrase for a Cotton Club production number in 1931, little did they know that "I Love a Parade" would become one of those expressions that make an indelible imprint on a culture -- one of America's self-evident truths.

But the truth may have outlived the evidence. Do we still love a parade? How many of us in the nation's capital know -- or even care -- that a three-hour Independence Day parade kicks off along Constitution Avenue today at noon?

"Part of our pop mythology is that, gee, everybody loves a parade," says Otto L. Sonder Jr., chairman of the department of sociology and anthropology at Hartwick College in Oneonta, N.Y.

"But to a lot of people in the modern world, parades are boring. They've seen it all before. What's so exciting about 10,000 people walking along the street, wearing strange outfits, beating drums, twirling batons? You can see endless people, strange things, excitement every day on a TV screen in your home."

That's not to say that drill teams and majorettes perform to empty curbsides in the '80s. This year's Tournament of Roses parade attracted more than a million pushing and shoving people along its five-mile stretch in Pasadena, Calif. Two million New Yorkers turned out last year to hail U.S. Olympians with a ticker-tape parade. And about 500,000 people crushed downtown Washington in 1981 to cheer on the caravan of 53 hostages freed from Tehran.

But, says Marcus Cunliffe, a British professor who teaches comparative civilization at George Washington University, "parades are never as good as they were." He agrees with Sonder that "in earlier times, parades were more dynamic and more important to individuals and to the community." Now, "if it's a hot day and you can stay home . . . you're not going to show up for the parade."

Early parades in this country were, by definition, military. Muster Day, a popular quarterly "exercise" of arms, required by law that all able-bodied militiamen present weapons for inspection. The entire community turned out for it. A second parade day, especially in New England, was Pope's Day. Raucus, anti-Catholic mobs marched the streets with effigies of the pope and anyone else they didn't like. Come the Revolution, the king of England replaced the pope as the figure of derision.

"There was a great need to quickly create a feeling of 'we-ness' -- ethnocentricism," says Sonder. "July Fourth is a good example. The colonists needed that feeling: 'we' against the British. The parade phenomenon was terribly necessary."

Solidarity and identity are the cause and effect of parades, according to Thomas N. Brown, professor of history at the University of Massachusetts and an expert on nationalism. "Historically, their basic purpose was to demonstrate solidarity. You had the early political communities called states, cities and towns. People like Washington, Hamilton and Adams, all federalists, contrived to build this larger thing called the federal government. They encouraged ritualized expressions of this embryonic sense of nationalism and they did this through parades."

Although early detractors of federalism thought parades celebrating the nation marched at the expense of local identity, Brown says local pride and identity was in fact reaffirmed. "Parades in this country traditionally healed differences and antagonisms, enabling the local communities to come together."

Social psychologist Karl Hakmiller calls "feelings of cohesiveness" the most vital psychological benefit parades have to offer. "What does that parade do for us?" asks the University of Connecticut professor. "It's an opportunity for people to say, 'You're here and I'm here, and we're all part of the same group.' It gives us a feeling of belonging. And that makes people feel good."

While a parade stimulates a feeling of togetherness, Sonder says it simultaneously strengthens the opposite -- the "I" emerges within the crowd. "The rhythm of the music, the physical vibrations of the pavement, the mere fact of numbers of people marching . . . and the notion that 'I am part of something bigger' restores a sense of self-awareness," says Sonder.

The growth of "self" in modern parades has led some experts to conclude that their nature may be changing to reflect more closely the pluralistic self-centeredness that marks society today rather than yesteryear's spirit of '76.

It's a difference clearly seen in the parades of small towns versus large cities. Says Hakmiller: "In small towns, particularly where people you know are participating, everyone loves a parade. In big cities, where there isn't much cohesiveness and you don't know anyone . . . it can be a pain in the neck. Small towns are where the parades happen spontaneously. In big cities, parades are sponsored by the government. The country is no longer one community. Everybody has his own community."

While parades have historically exhibited special interest themes, such as traditional St. Patrick's Day and Columbus Day parades, the intent in the past has been cultural assimilation -- becoming part of the greater whole. Today's special-interest parades, says Cunliffe, can be assertive.

"Private groups tend to assert their own rights, particularly minorities," he says. "You tend to have less emphasis on some things as they lose their function or interest. Italians, for instance, don't need to assert themselves so much anymore, do they? So Columbus Day parades have diminished. St. Patrick's Day parades tend to be less the minority statement now and more just a good time.

"But as society permits, we can expect to have a lot more parades as demonstration of some form. You can get enough people to make it a big public spectacle and you can make your point."

On a single weekend along Constitution Avenue last October, an estimated 15,000 Buddhists displayed flags and fireworks in a spirited parade, followed the next day by the National Firefighters Parade and a makeshift Columbus Day Parade -- the first in recent memory -- staged by 300 Italian-Americans seeking to regain the spotlight.

Cunliffe and Brown characterize Gay Pride parades in Washington and in other major cities as self-interest parades typical of our times that enhance a sense of specific community over larger community. "What appears to be true of the gay parade is that they are very provocative," says Brown. "Maybe what you have in that case is a group that feels itself estranged from the community, that draws its strength and sense of self by the very estrangement from the community. The remote goal is to alter society -- not to reaffirm it."

Cunliffe recalls a Native American Movement parade a few years back that, he says, was "counterproductive" because the participants were caught between assimilation and assertion. "They didn't have very many people," he says. "There was no music and they wore regular street clothes with almost no costumes. If you want to make an impression, there's got to be an appeal. Make the audience enjoy it, have music. You've got to say 'Look at us, we are part of you.' Or at least say, 'Look at us.' "

Observers disagree on the future of parades.

"I have a feeling in 20 years, we'll be talking about parades only in the historical context, in the past tense," says Sonder. "The parade was a different circumstance in a rather humdrum world of the past. It used to be the ritualized kicks and jollies. We could always plan on going down to Main Street on July Fourth to watch the marching bands and veterans go by. But now the parade isn't that exciting. Times have changed."

Hakmiller disagrees. He foresees "parades and events that bolster a sense of belonging in small, suburban communities that are growing in strength" to become more prevalent. Residents of Vienna, Va., might agree: In 1980, a single high school band, a handful of local politicians, a Postal Service jeep or two, and Joe Theismann turned out for a good, old-fashioned parade -- to honor the town's ZIP Code. Since then, other towns across the country have done the same.