What was going on when I was born?

For many Americans, finding ways to justify writing off trips, meals, parties, a portion of the house and all sorts of other expenditures as business expenses is a challenge. And indeed, business-related deductions can be quite lucrative. But the rules are strict and the territory is a favorite stomping ground for Internal Revenue Service auditors who look for business write-offs that are, in reality, more personal in nature. But if a substantial business connection can be drawn, the cost of a trip, a night on the town, lunch at the Four Seasons or even a room in one's house may qualify for a deduction. Deductions for Employees People who run their own businesses or operate sideline businesses have greater opportunities for business deductions than do employees.But employees are entitled to deduct many types of out of pocket expenses incurred for their job or while trying to land a better one.

The United States said today that New Zealand had ''definitively turned down'' an American request for a port visit by a Navy destroyer because Washington would not say if it carried nuclear arms. American officials said the move, announced today by Prime Minister David Lange, threatened the future of the South Pacific alliance of the United States, New Zealand and Australia. The State Department said tonight that naval exercises planned next month by the three countries had been canceled because of New Zealand's action. Viewed as a Test Case The Reagan Administration had made the proposed port call a test case of New Zealand's seven-month-old an tinuclear policy and had indicated that a rejection would lead to a reap praisal of the alliance, known as Anzus.

All 250 officers in the Emergency Service unit of the New York City Police Department decided yesterday to demand transfers, the head of their union said, to protest the indictment of a fellow officer in the death of Eleanor Bumpurs. The officers - all volunteers in a special unit trained for rescue work and for dangerous situations ranging from subduing emotionally disturbed people to dealing with terrorists - called upon the city's 18,000 police officers to refuse to replace them. In another reaction to the indictment last Thursday in the Bronx of Officer Stephen Sullivan on a charge of second- degree manslaughter, the union representing police officers issued a ''Use of Force Doctrine'' on how to arrest or restrain people in situations that were not considered life-threatening. To Await Instructions The union, the Patrolmen's Benevolent Association, suggested that officers in all the city's boroughs refrain from any action until directed to do so by a higher-ranking supervisor and that in the Bronx and Brooklyn, officers should also await instructions from a prosecutor.

Despite bipartisan criticism of President Reagan's proposals for sweeping cuts in domestic programs, his 1986 budget package is being treated more seriously than his last two budgets as a framework for squeezing Government spending and curbing deficits. The political climate is not as good for the President as it was in his 1981 heyday with Congress, top Administration officials concede. This year, they reason, his budget-slashing lacks the novelty of the first Reagan program, confronts more powerful middle-class constituencies and must carve large savings from a narrower slice of the total budget. Chance to Pare Deficit Nonetheless, Administration strategists contend that with the economy now strong and the President riding a surge of popularity, the next six months offer the best and perhaps the only opportunity for a major assault on the deficit problem in Mr. Reagan's second term. They see little prospect of major advances in 1986, an election year, and afterward as the President's lame-duck power wanes.

The American Telephone and Telegraph Company is preparing to enter the videotex business in a joint venture with Chemical Bank, sources in the industry said today. The venture is also expected to include Time Inc. and the Bank of America as smaller participants. The venture would provide electronic information services, such as home shopping, news and ticket reservations, to consumers with home computers or special terminals. It is expected that Chemical Bank's Pronto home banking service would be a major part, at least initially, of the services offered.

The most significant political trial in post-Tito Yugoslavia ended today with the conviction of three dissidents on charges of disseminating ''hostile propaganda'' against the state. In a verdict that was watched as a possible harbinger of a sterner line, the judge sentenced one defendant to two years in prison, another to 18 months, and a third to one year. All three men are free pending appeal. Milovan Djilas, the prominent dissident, who was not on trial, said in an interview after the sentencing that he interpreted the verdict ''as a bad sign for the development of Yugoslavia.''

PSYCHOLOGISTS, using modern research methods, are probing one of the universal themes of human existence: the anguish that follows the death of a loved one. In part, they are confirming the wisdom of some ancient responses to death. For example, a recent report from the National Academy of Science concludes that rituals such as the Roman Catholic wake and the Jewish custom of sitting shivah are increasingly important in modern society. The rootlessness of contemporary life, the report points out, leaves little time or place for the expression of the deep feelings that mourning brings. The old rituals, however, signal that the feelings of grief have their rightful place in life. The current studies, a melange of loosely connected observations from the work of many researchers, are attempting to go beyond earlier thinking on mourning.

Companies G.M. earnings slid 32.4 percent in the fourth quarter, to $877 million, but still reached a record for the year of $4.52 billion. The quarter's net was hurt by work stoppages and production delays, G.M. said, but the results were within analysts' expectations. (Page D1.) William E. Hoglund was named to head G.M.'s new Saturn subsidiary, giving him control of one of the company's most visible and innovative units. (D4.) Norwest is holding preliminary talks with G.M. on the possible sale of its mortgage-banking unit. (D4.) A.T.&T. is preparing to enter the videotex business in a joint venture with Chemical Bank, sources said. The venture is also expected to include Time Inc. and the Bank of America. (D1.)

Prime Minister Shimon Peres expressed disappointment today with what he described as Egypt's failure to respond to his efforts to improve relations between the two countries. Mr. Peres added that if Egypt's cool attitude toward Israel continued, there was a danger that the forces for peace in Israel would become discouraged and question the value of efforts to normalize relations with Arab neighbors. Mr. Peres's remarks about Egypt came during an hourlong interview in his Jerusalem office and were his first public criticism of the Government of President Hosni Mubarak since becoming Prime Minister last September. Peres Shows Frustration While Mr. Peres has expressed admiration for Mr. Mubarak, his statements today reflected the mounting frustration in his administration over the continued absence of normal relations between Egypt and Israel, despite what Mr. Peres sees as genuine efforts on his part to satisfy Egypt's conditions for returning an ambassador to Tel Aviv and warming up the so-called cold peace. Asked if he was satisfied with the state of Egyptian-Israeli relations in light of the recent deadlocked talks in Beersheba over the tiny disputed Taba border strip, Mr. Peres said: ''Frankly, I wish it could go a little bit further than it does. You see some Israelis can say, rightly, 'Look, the Arabs want land for peace.' In the case of Egypt, 99.999 percent of the land was returned and many Israelis are asking, 'Did we get 99.999 percent of peace?' ''

The natural gas the Saudi Arabians once wastefully flared off as a byproduct of oil production is now being harnessed and turned into petrochemicals. The Saudi dream of industrialization is coming true. But some analysts are suggesting that the dream may turn into a nightmare for petrochemical producers elsewhere - with Dow Chemical, Union Carbide, Du Pont and the European and Japanese chemical giants all feeling the effects. In picture-book communities and gleaming plant complexes that did not exist five years ago, Saudi Arabia this year is starting up much of its output of products with such names as ethanol, methanol, polyethylene and polyvinyl chloride.

Stock prices shot up yesterday, resuming their four-week-long rally after a one-day setback on Friday. ''The market has shrugged off its momentary worry that interest rates might tighten up again, to come back with a very powerful performance,'' said Thom R. Brown, executive vice president of Butcher & Singer Inc. in Philadelphia. The Dow Jones industrial average jumped 12.36 points, to 1,290.08, close to its record of 1,292.62 set last Tuesday. Broader measures set records, as they did last week. The Standard & Poor's 500-stock index gained 1.72, to a new high of 180.35. The New York Stock Exchange composite index of more than 1,500 stocks climbed 0.93 point, to 104.16, also a record.

AS sales of aspartame, the nation's newest artificial sweetener, expand rapidly among millions of users, scientific concern is also growing among some researchers about its safety. The researchers are alarmed by recent reports that a small percentage of users, including at least two young children, may have suffered severe adverse reactions to aspartame. Especially worrisome are reactions involving the brain, including seizures, incapacitating headaches, dizziness, behavioral changes and depression. There is also concern about the possibility that in a larger percentage of consumers, aspartame may cause subtle disruptions in the balance of brain chemicals that influence mood, alertness and hunger for certain nutrients. To date there is no evidence in people of such effects, but investigation of the matter is only now beginning.