Liberated from the dark collective label of "hostages," 41 Americans came forward today for their first formal press conference since their release from captivity in Iran.

Fresh from their first thanksgiving dinner, first hangovers, and a variety of other firsts after 14 1/2 months, the performances of these men and women whose faces have haunted the nation ricocheted from the cockiness of the young Marines to the deft eloquence and wit of the diplomats.

Their determined good humor contrasted starkly with the fragmented accounts of beatings, solitary confinement, and other abuses that have emerged in recent days. Indeed, they seemed almost purposefully to downplay the torture and hardship they have endured.

Asked about the reports of "mental problems" among at least a dozen of them, Marine Sgt. John D. McKeel Jr., 27 stuck out his chin and drawled, "I don't know how the rumor got out about some of us hostages supposed to be mentally disturbed . . . as soon as they let us get home, especially the Marines, get back to chasing women. . . . We are all right, physically and mentally."

Asked if Washington should have known better than to let the shah into the United States, political officer John W. Limbert Jr., 37, who speaks fluent Farsi, and has a Ph.D. from Harvard, replied delicately: "When you're in the embassy in Tehran, or wherever, it seems that Washington should always know better. This is natural. This is natural about Foreign Service officers."

Bruce Laingen, 58, the ranking diplomat among them, served as moderator for the former hostages.

To the press assembled before him with their lenses and lights trained on the stage like artillery, he noted mildly, "We've been somewhat out of touch."

He asked for understanding and urged the horde not to "press us too hard . . . we're not all that dept at prress conferences, certainly not with such a vast throng of earger faces. . . . Also, I think we need time to reflect a bit so that in terms of policy questions, and things bordering on substances, I ask your understanding. . ."

Though some of the several hundred reporters and TV camera crews had been standing in line outside since 5 a.m. to be assured of a good seat in the military academy's huge auditorium, most of them complied happily with his request.

The returned hostages succeeded in sidestepping almost entirely the sort of grim stories they have been providing individually to their families and the press about the conditions of their captivity.

Near the end of the press conference, Virginia Wohl, who described herself later as a supporter of the Revolutionary Communist Party, a Maoist group, grabbed a mike to ask a hostile question about alleged U.S. support of torture under the shah, and also about an Iranian charge that Laingen was a CIA agent. The press helped drown her out with other questions while political affairs officer Victor L. Tomseth let out a loud mirthful "Ha!" at the reference to Laingen.

Laingen set the tone of the whole gathering in his opening statement, which looked to the present mood of celebration and to the future and ignored, the bitterness of the long ordeal.

"On this beautiful morning at this beautiful spot on the Hudson River, I am proud to present to you 52 equally proud, free and happy Americans. I can tell you also that behind the curtains over there sit our families, some of the most beautiful people in the world as far as we are concerned."

Behind the curtains separating them from the television cameras, the families could be heard laughing mischievously from time to time at some witticism or "in" joke delivered on stage.

The freed hostages have been "humbled by what we have seen of the magnificence of the support" from their countrymen, Laingen said. "To paraphrase, never has such a small group owed so much as so many. . ."

Of their welcome home Sunday, he added, "we saw that and we knew we were home. We saw that and we knew America was well. . . . we saw it not simply as a welcome to us, 52 people, but as evidence that the spirit of America is strong, and America has heart, and America is prepared, as it has always been . . ., to reach out to people in distress."

The press applauded as the 41 strolled onto the big stage at the Eisenhower Auditorium, perched on a bluff over the Hudson River. They carried their identities on name placards to be placed in front of them on the blue-draped tables, next to the microphone and the pitcher of water.

Looking much like a lineup of contestants for "Hollywood Squares," they sat for several minutes, squinting into the glare of television lights, while the press scrutiny of their pale drawn faces became almost palpable. Some frowned, others wore bemused little smiles as they stared back at the scruffy-looking crowd that was about to interrogate them.

They were dressed to the nines in new uniforms or civilian dress for a day on which they would meet the new president. Attendance at the 9 a.m. press conference was voluntary. No explanation was given and no questions were asked concerning the 11 who were not present: Claire C. Barnes, Donald J. Cook, Duane Gillette, Donald R. Hohman, Frederick Lee Kupke, Michael J. Metrinko, Jerry J. Miele, Gregory A. Persinger, Jerry Plotkin, Joseph Subic Jr. and Phillip R. Ward.

A State Department spokesman said it would be an "invalid assumption" to believe that the people who did not attend the press conference were the same ones who haver reportedly been suffering from serious psychological problems. "Some of the very people who have been subject to this speculation are the ones who turned up at the press conference," the spokesman said. "I'm not naming any names, but attendance at the press conference was purely a matter of personal choice."

Warming to his resumed role as a diplomat, Laingen thanked a long list of players in the hostage drama, including all of the other governments who helped with the negotiations for their release, his fellow hostages, those released earlier, and the people in and around their secluded quarters at West Point's Hotel Thayer, which he referred to as "this embassy in exile." w

A burst of laughter came from the families backstage when Laingen thanked Ireland. It was there that the freed hostages' homeward-bound plane had stopped for refueling and some of their group "refueled" on Irish whisky and other native products.

Some of the hostages, while avoiding dramatic or controversial revelations, offered insights into the nature of their captivity and of their captors. Tomseth provided an insider's confirmation of reports that a member of the Islamic religious faction in Iran was a guiding influence for the group of student-terrorists that seized the U.S. embassy.

"In dealing with Iran . . . there was always a question of who's in charge and [the possibility] that nobody's in charge and everybody's in charge. And it was fairly clear to us that the students did have at least one mentor in the person of a mullah by the name of [Mohammed] Mousavi Kho'ini, who certainly, subsequent to the seizure of the embassy, played a fairly important role within the government. . . .

"My own view," Tomseth went on, "is that it is not very likely that there was prior knowledge, at least not to any extensive degree, within the formal government at the time . . . regarding the plans to seize the embassy, although several of the students and this mullah did indicate, subsequent to the seizure, that it had been in accordance with a previous plan."

Tomseth, who along with two others, including Laingen, was captured and held at the foreign ministry in Tehran, also dismissed as "unlikely" continuing rumors that either the Palestine Liberation Organization or agents of the Soviet Union had a hand in the hostage seizure. On a subject that continues to be controversial -- the validity of the deal worked out with Iran and the question of whether the United States should negotiate with terrorists in any circumstance -- Laingen and Steven Lauterbach, 29, a State Department administrative employe, volunteered that they supported the negotiations and the agreement.

Laingen and others paid tribute to the eight servicemen who gave their lives in the failed resuce raid last April. The only other comment about that event was to the effect that the returnees do not yet have full information on it. Earlier, some ex-hostages such as Moorhead Kennedy said they believe the raid was ill-advised and would have cost the hostages their lives.

At least two former hostages tried to correct what they saw as distortion or outright inaccuracy in press accounts of their captivity.

"I'm uncomfortable," said John E. Graves, 53, a public affairs officer at the embassy, "with the fact that much of what I see in the press seems to be a kind of almost willful distortion or deluding, or sort of wishful thinking. I think there's enormous evidence, truly cogent evidence, for the proposition that the people who . . . captured us were legitimate students. I don't think there's any doubt of that at all."

As to their goals, he said it was too complicated a subject to go into for the moment, but "I can tell you . . . they were not interested in the outset in getting the shah back. It was a pretext."

Elizabeth Ann Swift, 40, ranking political officer for the embassy, said she was "very concerned" over a Newsweek article quoting her on torture. "I never talked to anybody from Newsweek. I never said this to anybody, any other correspondent, and it's not true."

[A Newsweek editor said last night that the magazine was attempting to determine the accuracy of the quote, which he said first appeared in a German newspaper.He also said that the magazine has sent Swift a letter expressing "distress at the incident and apologizing for it."]

The giant (6 foot 9) William F. Keough Jr. spoke from his perceptions as a school teacher. Assigned to a school in Pakistan and on a school board payroll, not federal, he had just stopped off at the embassy to pick up some records on the day the hostages were seized.

On the faces of the cadets at West Point, who were about the same age as the students, he saw "on each and every face . . ., over a smile, determination." On the faces of the students in Iran, he said, there was "anger and anarchy."

William A. Gallegos, 22, an embassy guard, was asked about the tape he made in captivity saying his treatment had been good.

"I don't know if you understood, but . . . my peers in the military understood what I was trying to say . . . that the treatment was good for my fellow colleagues so that they would not be mistreated. But also I was trying to say that we were not being treated well."

Doctors say that some of the captives forced to make such tapes by the Iranians are suffering feelings of guilt.

The reporters in many cases treated the former hostages more like returning hometown heroes than subjects of interviews. One reporter combined a welcome-home message to Dallas men Robert Engelmann and John D. McKeel Jr. with a question about their "mental problems." When everybody laughed, the reporter quickly added, "Oh, not specifically you. But everybody." More laughter. Engelmann responded, "It was a period of extreme stress, but what impressed me most . . . was the ability to just close the door on it that we all seemed to exhibit" once aboard the plane in Tehran. "We had forgotten a lot of it. A lot of the stress was relieved just by walking on board that aircraft."