The rate of increase in college tuitions moderated slightly this year, but continued a decade-long trend of outpacing inflation, according to an annual College Board survey released today.

The survey of 2,822 colleges found that the average charges for tuition and mandatory fees rose 8 percent at private four-year colleges and 7 percent at public four-year colleges. Both figures were down 1 percentage point from 1989, representing the first joint decline since 1984.

Higher education representatives attributed the slight price moderation to cost containment, especially at private schools, and political pressure to hold down public college tuitions, particularly in states such as New York and North Carolina where large numbers of students are enrolled. Also cited was consumer reaction to the ever-rising price of a college education.

Students are paying an average of $9,931 in tuition to private colleges and an average of $1,809 to public colleges.

"For some schools -- certainly not the most elite schools -- there's a point when increased tuition results in fewer applications and may even lower enrollment," said Dave Merkowitz, spokesman for the American Council on Education. "Schools . . . don't want to price themselves out of their market."

Bennington College, a small fine arts school in Vermont, again reported the nation's highest tuition at $17,790. Massachusetts Institute of Technology had the highest overall total for tuition, fees, room and board, books, transportation and personal expenses (clothing, laundry, entertainment and medical insurance): $22,945. Other elite schools in the Northeast are charging a few hundred dollars less.

Nationwide, average tuition increases again exceeded the inflation rate, which was 4.7 percent for the 12 months ending in June. Higher education representatives offered the same explanations as they did during the 1980s, when tuition hikes averaged more than 9 percent: They reflect costs of faculty salaries, building repairs and equipment such as computers.

"We're facing very real costs, and until we bring the costs down, we can't do very much about moderating tuition increases," said Richard F. Rosser, president of the National Association of Independent Colleges and Universities.

Rosser said an ongoing Justice Department probe of possible antitrust law violations in pricing policies at 57 colleges had "nothing whatsoever" to do with the dip in tuition hikes.

Donald M. Stewart, president of The College Board, decried "the tendency to focus on the cost of a relatively small number of high-priced colleges." He noted that almost half of four-year colleges charge less than $5,000 for tuition.

Meredith Ludwig, research director for the American Association of State Colleges and Universities, said public tuitions did not reflect the impact of recent shortfalls in many state budgets. In some states, she said, the possibility of mid-year surcharges or fee increases looms if state appropriations are reduced.

Researchers have found evidence that tuition hikes of the 1980s have affected students' college choices. Tom Mortenson of the American College Testing Program has reported that middle-class families with incomes too high to receive federal aid have gravitated to less expensive public colleges.

The main reason for the increasing popularity of historically black private colleges, according to the United Negro College Fund, is that their tuitions have averaged half the charges at their predominantly white counterparts.

Education Secretary Lauro F. Cavazos, commenting on the survey, said: "While the rapid rise of college costs experienced in the 1980s has slowed, many still perceive these costs as beyond their financial reach. I urge anyone thinking about higher education in the near future to begin investigating financial aid opportunities."

Among Washington area institutions, Georgetown University continued to charge the most for tuition and fees: $14,569, a 9 percent increase. Other increases at local schools were: American University, 10 percent to $12,648; Catholic University, 8 percent to $11,065; George Washington University, 18 percent to $13,950; and Howard University, 8 percent to $5,905. Annual charges at the University of the District of Columbia remained unchanged at $664.