What was going on when I was born?

Terra cotta treasures from the ancient West African civilizations of Mali and Ghana are on view at the African-American Institute, First Avenue at 47th Street, through Jan. 9. Most of the 59 sculptures date from the 12th to the 17th centuries and include Akan works from Ghana created solely by women. The oldest item is a ninthcentury snake head. On Second Avenue, at 56th Street, an exhibition of Japanese ceramics is on through Oct. 25 at the Old Horizons Gallery of the Manhattan Art & Antique Center. The 19 pieces, from the 15th to 20th centuries, include items used in the traditional Japanese tea ceremony. Both exhibitions are free. CANADIAN BRASS ON L.I. Members of the Canadian Brass take their music, but not themselves, seriously; they always include a few ''choreographed'' pieces, and they always chat. Their program tonight at 8:30 at the new C.W. Post Concert-Theater, off Route 25A in Greenvale, L.I., ranges from Bach to Fats Waller and includes a ''Killer Tango,'' which pairs the two trumpet players in some appropriate footwork. The event opens the ''great performances'' series of Friends of the Arts. Single tickets are $10. Reservations are suggested: (516) 922-0061.

AS the art season goes into high gear, SoHo, alive with artists, galleries and those who come to look at both, is drawing its usual crowds. This year, expectations are high, generated not only by the prospect of a bustling art season, but also by the promise of new directions in it. After a decade of Minimal and Superreal, there's a new interest in the bold Expressionist work of young artists from Europe such as Reiner Fetting and Enzo Cucchi, as well as Ken Kiff (who can be seen in SoHo), and in the streetwise, high-energy art of the so-called New Wave, which is influenced by punk rock and the popular media. In range and in the number of qual- For some suggestions on where to dine when in SoHo, see page C20. ity art dealers, SoHo is still an outpost of the uptown scene, where art from the oldest masters to the newest yougsters is plentifully purveyed. But the small, crowded quarter downtown, with its narrow, intimate streets, its casual drop-in cafes and the sense of a creative community that it retains despite the invasion of uptown chic, seems to be a more relaxed place for people to meet, talk and buy contemporary art than the chilly canyon of 57th Street.

The Polish Government and the independent Solidarity union agreed today on a temporary freeze on price increases until a system of compensation for the lowest paid workers could be put into effect. The agreement, reached at the start of the first negotiations since August, applies to all but increases in gasoline and alcohol prices. It seems to represent a concession by the Government, which planned to introduce a series of price rises to reduce the drain of subsidies for a wide range of food and consumer products. Union members had been angered by a doubling of cigarette prices and increases in the cost of fish and canned fruit that went into effect last week during the closing stages of the union's national convention.

Elias Canetti, a 76-year-old writer whose books stem from the vanished cosmopolitan traditions of Central Europe, was awarded the Nobel Prize for Literature today. Mr. Canetti, who writes in German, was born in Bulgaria, educated in Switzerland, Germany and Austria, and is living in London. He was cited by the Swedish Academy for his ''writings marked by a broad outlook, a wealth of ideas and artistic power.'' He is the first native of Bulgaria to win the prize.

''ART of the Avant-Garde in Russia: Selections From the George Costakis Collection'' at the Solomon R. Guggenheim Museum is the latest in what is by now a long series of exhibitions devoted to one aspect or another of avant-garde art in Russia between 1910 and 1930. London, Paris, Los Angeles and Washington - in that chronological order - have all had substantial exhibitions of this kind. But if New York in this context has taken its time, the Guggenheim show is a remarkable affair and rich above all in small-scale lyrical work that comes across with a remarkable freshness. Quite apart from that, there are artists in the show - among them Varvara Stepanova, Nadezhda Udaltsova, Olga Rozanova and Gustav Klucis -who make an effect of unexpected strength and variety. This is a show to remind us how Rozanova once said, ''Nothing in the world is more awful than the unchanging face by which an artist is known to his friends and collectors.''

President Reagan called on the third world today to develop free-market economies to break the grip of poverty. In a speech delivered a week before he flies to Cancun, Mexico, for a conference on world economic development, the President outlined a development strategy that emphasizes the advantages flowing from free enterprise, investment and trade. He proposed no major new initiatives for Cancun, noting that he was going ''to listen and to learn.'' But in remarks to Excerpts from speech, page A12. the World Affairs Council of Philadelphia he said that the United States was already ''leading the way in helping to better the lives of citizens in developing countries.''

The Rev. Sun Myung Moon, head of the Unification Church, was indicted in Manhattan yesterday on charges that he had filed false tax returns omitting more than $150,000 of his income in a three-year period. According to the indictment, Mr. Moon deposited $1.6 million in New York bank accounts in his own name, used the money for his own purposes and failed to report almost all of the interest, amounting to more than $100,000, from 1973 through 1975. It also said he had failed to report $50,000 in securities that he had received in 1973. The 12-count Federal indictment also charged one of his top aides, Takeru Kamiyama, with assisting him and with committing perjury and obstructing the investigation.

The Senate today unanimously approved legislation designed to preserve the solvency of the Social Security System through the 1980's. The 95-to-0 vote also retained the minimum benefit for all those now receiving it, reversing an action taken last August. The measure now goes to the House, which is expected to concur within a matter of weeks. The Democratic leadership there has endorsed the two major features of the bill, and no serious opposition is expected.

A crowd of 2,000 people turned out yesterday to seek applications for 126 Manhattan apartments whose tenants will receive Federal rent subsidies. A melee that erupted as some of them pushed and shoved one another forced the organization dispensing the applications to call the police and turn away almost all the apartment seekers. William Baldwin, housing director of the organization, the Manhattan Valley Development Corporation, and others involved in neighborhood housing efforts, said the incident illustrated the ''desperate need'' of many poor New Yorkers for decent, affordable housing. Mr. Baldwin said the incident showed that ''the pressure for housing among the poor has increased dramatically in the last year.'' ''These people feel that soon there's isn't going to be any place for them to live,'' he said.

President Reagan outlined a third world development strategy, stressing the advantages that arise from free enterprise, investment and trade. In a speech before the World Affairs Council of Philadelphia, the President depicted economic and political freedom as the key to prosperity. (Page A1.) An end to OPEC's bitter oil-pricing battle seems near. A preliminary accord is said to be possible as early as Thursday, when world leaders meet in Mexico; four OPEC members will be represented. In the past week, two opponents of Saudi efforts to force a price rollback have softened their positions. (D1.)

A 37-year-old man who lives a block from the burned-out building was arrested and charged with eight counts of homicide and one count of aggravated arson. The fire in the 16-family building at 89 Park Avenue erupted about 3 A.M., and many of the victims were trapped in their apartments as they slept. Six bodies, apparently all from the same family, were found in a third-floor apartment. Two other victims were found in apartments on the fourth floor, fire officials said.

The cinder-block walls are painted glossy white. Women work quietly with circuit boards and multicolored wires along the rolling assembly lines. Rosenda Vazquez, who has worked in this factory for 15 years, turns to a testing meter at her side. She links a wire from it to one of 400 chassis for 19-inch Quasar color television sets that will pass her station this day. The meter sweeps to the right, as it should, and Mrs. Vazquez returns the chassis to the clanking line. She rarely spots a faulty connection these days. ''Before, there were times when people just gave up'' because there were so many mistakes to correct, Mrs. Vazquez said. ''We recognize now the importance of doing the job right the first time.''