IN the popular comic strip ''Doonesbury,'' artist Garry Trudeau frequently poked fun at college reunions. Once he showed three alumni from the class of '43 with straw hats and buttons, one trying to impress the others: ''. . . After that, I joined Merrill Funds, and it's been gravy ever since. But Howie, how about you? What have you been up to all these years?''
''Me? Oh, I still haven't made up my mind what to do yet. . . . I just don't want to rush into anything.''
This scene portrays college reunions as occasions to impress or to be impressed, to compare oneself favorably or unfavorably with others. But a number of reunion-goers sampled by this reporter see things differently.
Christopher Hammond, who went back for his fifth reunion at Pomona College, in California, says, ''College is kind of like a benchmark. It's comforting to go back and see where you've been.'' Mr. Hammond, assistant vice-president of a Los Angeles bank, wanted to see how his friends had developed. He says no one at his reunion seemed very concerned about success yet.
By his 25th business school reunion, says Northwestern alumnus Richard Steen, success was a factor in bringing back alumni, but not the only factor. ''Those who came back were reasonably successful in life, and they wanted to hear about the others or, most of all, talk about their own success.''
American University alumna Lois Colison attended her 50th last year. By this reunion, often a school's biggest, nostalgia and strong college ties, not the desire to impress, draw alumni back, she feels. ''When people reach the 50th they're mostly retired,'' she says. If you had made a big splash in the world, people knew it. But people mostly exchanged information on where your children were, and so on.''
One purpose for reunions, of course, is fund raising. Mr. Steen, who was a member of Northwestern's board of regents for a dozen years and its chairman for three years calls them ''fertile ground for raising money. . . .''
The intangibles, though, are what alumni remember and what planned activities help to foster. Jack Riehl, former alumni director at Whitman College in Washington State, says that these activities should encourage people to ''share a common past, rekindle the same spirit they once enjoyed, and reestablish their link with the college.''
To accomplish this, colleges usually plan some activities for all returning alumni and let individual classes arrange special events of their own.