Geraldine A. Ferraro today abruptly challenged an audience of students to "tell me why we're losing you" to the Republican Party.

Moments after concluding her most extensive foreign policy speech of the campaign, the Democratic vice-presidential nominee surprised her aides by pleading for "somebody to get up and talk to me" about why "young people are moving toward the Republican ticket."

She persisted until the University of Washington students began to open up.

"The reason, from what I know about the majority of my friends who are for Reagan-Bush, is they're afraid of another embarrassing four years like 1976 to 1980 . . . . I'd rather have President Reagan in control of me than Democratic nominee Walter F. Mondale," said a young man in a lavender sweater who identified himself as a Marine.

"It seems like they're like Reagan," a young woman in the balcony said of her peers. "It's all about me, and not we. They don't care about South Africa. Who cares? It's about how can I put a dollar in my pocket?"

"The failure of the Democrats," another young man suggested, was in failing to persuade Americans that their global interests transcend individual interests.

Ferraro used a similar confrontation with considerable drama in a meeting with Illinois auto workers Oct 2. As she did with the auto workers, Ferraro today tried to rebut point-by-point the student arguments.

She reminded them that the 52 U.S. hostages in Iran all came home alive, that nearly twice as many jobs were created during President Jimmy Carter's term as in Reagan's, that many economists believe that the current economic recovery lacks a firm foundation and that the administration has sought deep cuts in food stamps and nutrition programs.

"I don't want to lecture you," she said. "That's the furthest thing from my mind and my heart at this point. But let me just tell you, we must care about others."

Several students afterward said they were impressed, but not persuaded to vote for the Democrats.

"I've always liked everything she's said. But I don't like Mondale and he's running for president. He's too indecisive. He's going to be another Carter," said Christine Herrmann, 18, a freshman from Walla Walla.

Aides said Ferraro is perplexed about what the Republican allure is for people who normally could be expected to embrace the Democrats.

"I think it genuinely drives her crazy," assistant press secretary Barbara Dixon said. "This gives her a chance to get rid of some of her frustration."

In Ferraro's foreign policy speech, aides said she foreshadowed some of the points Mondale will try to make in the second presidential debate Sunday.

"From South Africa to the Philippines to El Salvador, the Reagan administration has held out a hand to corrupt and brutal dictatorships," Ferraro said.

As an example of the administration's "moral blindness," she cited recent news accounts of a CIA manual that teaches assassination and blackmail methods to Nicaraguan rebels.

"This is totally contrary to our basic values," Ferraro said. "Anyone who believes that refining the murder techniques of Central Americans will advance our national interests is gravely mistaken."