As the nation looks back with relief at President Reagan's narrow escape from more serious injury in Monday's shooting, security officials are looking ahead to the immediate future with concern as they recall a chilling aspect of the last attack on a president. Just 17 days after one assailant pointed a gun at Gerald Ford in 1975, another disturbed person made another attempt on the president's life.

And those attempts by Lynette Fromme and Sara Jane Moore immediately prompted a rush of further spoken and written threats on the president's life. Then-Secretary of the Treasury William E. Simon said just after the second Ford incident that the number of threats against the president was triple the normal rate in the days following the two incidents. Publicity about assassination attempts "tends to invite . . . deranged human beings to come out," Simon said.

Security officials and psychiatrists say the increase in threats following an assassination attempt in a fairly common pattern; people who have had the idea of attacking a president somewhere in the backs of their minds tend to become more serious about it.

This poses a problem for Reagan and his advisers as they contemplate the conduct of the presidency when Reagan returns to the White House. Should the president purposely restrict his exposure to crowds -- one member of Congress, Sen. Larry Pressler (R-S.D.) proposed yesterday that Reagan limit future appearances outside Washington to military installations -- or should he make a point of emphasizing that his style in office will not be changed because of possible attacks?

Publicly, at least, Ford chose the latter course. Hours after a shot from Sara Jane Moore's pistol had sailed over his head, Ford vowed not to "cower" or "capitulate" to deranged persons. "If we can't have the opportunity of talking with one another, seeing one another, shaking hands with one another, or something has gone wrong in our society."

Reagan's chief of staff, James A. Baker III, said yesterday the administration is thinking about the possibility of reducing Reagan's exposure to large crowds in the future. But he noted that Reagan is an outgoing individual who enjoys contact with the people.

White House aides said it is possible that Reagan will wear a bulletproof vest in future public appearances -- such as he occasionally did during the 1980 presidential campaign. Ford began wearing a bulletproof vest after the attempts to shoot him.

Meanwhile, official Washington is considering the larger questions of how protection can be balanced against the interests of an open society.

Two congressional subcommittees have scheduled hearings today focusing on Secret Service procedures and the general problem of protecting a president. The Senate Appropriations Committee chaired by James Abdnor (R-S.D.) will question Secret Service Director H. Stuart Knight about protective measures in general and Monday's incident in particular.

Also today, a House subcommittee will question Treasury Secretary Donald Regan -- who has jurisdiction over the Secret Service -- about the same points. Another House subcommittee plans a private session with Secret Service officials to discuss details of Monday's shooting.

Sen. Edward M. Kennedy (D-Mass.), the younger brother of two men murdered by assassins, said yesterday that the attack on Reagan demonstrates anew the need for legal controls on handguns.

But congressional sources said there didn't appear to be much likelihood that the broad handgun restrictions Kennedy favors could be approved.

Reagan's closest aide, White House counselor Edwin Meese III, said in a television interview that he opposes gun-control laws. Where such laws are on the books, "so far, they don't indicate they really make much difference."