What was going on when I was born?

Governor Cuomo of New York and Governor Kean of New Jersey announced an agreement today to raise PATH fares and the tolls on the Port Authority's bridges and tunnels and then to channel the surplus revenues into regional development. These are the key elements of the agreement, as outlined in a joint letter from Mr. Kean, a Republican, and Mr. Cuomo, a Democrat, to the members of the board of the Port Authority of New York and New Jersey: - The fare on the Port Authority Trans-Hudson rail line, which has been 30 cents since 1962, would be raised to 50 cents as soon as the authority can hold public hearings and its board can act, probably in about six weeks, officials said. The PATH fare would go to 75 cents on Jan. 1, 1984. The extra revenue would be used for a $200 million program of capital improvements for the PATH system.

Two major bank holding companies, the Mercantile Texas Corporation of Dallas and Southwest Bancshares Inc. of Houston, yesterday announced an agreement in principle to merge in an exchange of stock valued at more than $515 million. The new corporation, to be called the Mercantile Southwest Corporation, would have 68 member banks and a combined asset base of $18 billion. This would have made it the nation's 20th largest at the end of 1982.

Orders placed with factories for durable goods rose a slight two-tenths of 1 percent last month, the Commerce Department reported today. The overall gain was the fourth increase in five months since the recession ended and recovery began in January. The May increase, however, was tiny in comparison with gains of 3.2 percent in March and 4.3 percent in April. The April performance had been estimated earlier as a rise of 3.8 percent.

After decades in Manhattan's shadow, downtown Brooklyn has the potential to emerge within a decade as New York City's third major business district after midtown and the financial district, according to a Regional Plan Association study. The study cites the proximity to Wall Street of an 89-block area near the Brooklyn and Manhattan Bridges, its confluence of subway lines and its favorable office rents. It urges the development of a large high-technology park, 10 million square feet of commercial space and up to several thousand housing units in the area. ''Its time has come,'' Mayor Koch said of downtown Brooklyn in introducing the study yesterday at City Hall and explaining why it stood a better chance of success than numerous predecessors that also urged concerted development in Brooklyn.

Palestinian guerrillas opposed to the leadership of Yasir Arafat overran eight positions belonging to Arafat loyalists in eastern Lebanon today with the support of Syrian troops and tanks, Palestinian officials said. The fighting was the first in which direct Syrian support of the rebels was reported and was the most serious clash yet between the factions in Al Fatah that back and oppose Mr. Arafat. Al Fatah is the largest group in the Palestine Liberation Organization's eightmember coalition. The factions have been fighting since May 15.

Some people keep them in safe-deposit boxes. Some frame them and hang them on their walls. Some have even used them for wallpaper. The world of New York-area residents who own bonds from czarist Russia and similar exotic securities is diverse though small. And now it is being shaken a bit by litigation. The city and its environs, bond experts say, are home to more than 25 percent of the thousands of Americans who own czarist, imperial Chinese and other bonds issued decades ago by monarchist or capitalist regimes of countries that have since gone Communist - and have refrained from paying off the bonds' owners.

''I want a budget resolution. Even though it's not good, it ain't bad.''

Underneath the oratory, another turning point occurred this week in President Reagan's relationship with Congress. Today, in fact, marked the abandonment by Mr. Reagan of the Congressional budget process that served him so well the last two years. The abandonment was made clear when Mr. Reagan today told Republican Congressional leaders that he would ''vigorously'' oppose the bipartisan $860 billion budget resolution worked out by House and Senate negotiators late Monday night. Last year and the year before, the President used the budget process to reduce Government spending by bundling together in one package an array of different spending measures and persuading Congress to approve it as the means to reach its own spending targets. That Mr. Reagan was thus walking away from the budget process, leaving some of his own Republican allies in the lurch, was the view today of those who both applauded and deplored his action. Where they disagreed was over the cost and risks involved.

Stacked on Wards Island in the East River are 169 wooden crates of chain. How they got there helps explain why high costs and new pricing formulas may transform New York from the nation's dominant general cargo port into a backwater of ocean commerce. The $53,000 worth of steel chain was ordered for a city sewage treatment plant. The manufacturer, Hitachi Maxco, shipped it from Japan - not to New York, but through its own warehouse in the port of Baltimore. From there, it was trucked to Wards Island. ''I'd do it again,'' said James Cunningham, the traffic manager at the company's City of Commerce, Calif., office. ''I saved at least a day or two days and probably $5,000 to $10,000 coming through Baltimore.''

THE high-fiber fashion, well into its second decade, has lost its faddishness and has become part of mainstream nutrition. With good reason: The more scientists examine fiber, the component of food not broken down by the digestive tract, the more they learn about its beneficial properties. And the more humans eat foods high in fiber, the more they discover how much they like them. This may be one of the first instances in modern culinary history where what's good for us to eat tastes good. An increased interest in ethnic foods - tostados with refried beans, chili, stir-fried Chinese vegetables and tabbouleh, to name a few - has proven that Americans will eat highfiber foods even though they don't think of them as healthful. Most of us consume high-fiber foods every day and never even realize it. Every potato, whether mixed with oil and vinegar dressing or served with yogurt, every pea seasoned with thyme or in a soup, every stalk of broccoli stir-fried with ginger, every peach, plum, blackberry or strawberry eaten out of the hand is a food high in fiber. As scientists learn more about the nature of fiber they have become increasingly interested in what are called soluble fibers, those that can leach out into cooking water.

AS a child with various minor allergies, I used to sneeze quite often. Each time she heard me sneeze, my grandmother would quickly bless me with ''zum leben un gesund'' (to life and health) and pull up on my right ear. Upon the inevitable second sneeze, my left ear would be pulled, accompanied by another blessing, ''zum wachsen un kwelln'' (to grow and thrive). With the wide prevalence of allergies to tree and grass pollen in the spring, mold spores in the summer, ragweed in the fall and animal hairs and house dust year round, conscientious Jewish grandmothers have done a lot of ear-pulling. What health significance does a sneeze have that it invariably invokes a blessing when no other human sound or emission is cause for a benevolent remark? As Dr. Selig J. Kavka, a Chicago internist, recently noted in The Journal of the American Medical Association, ''No routine comment is invited by someone belching, coughing, groaning, hiccuping, retching, snoring, vomiting, wheezing, or sniffing, even when these symptoms may portend trouble.''

Barbara S. Thomas, a 36-year-old New Yorker who is the youngest person to serve on the Securities and Exchange Commission, said today that she would be resigning for personal reasons ''sometime before the end of this year.'' The term of another member, John R. Evans, expired June 5. If he is not reappointed, and there have been indications he may not be, President Reagan will have the opportunity to appoint a commission entirely of his own selection; he has already filled three of the five commission seats. Mrs. Thomas, whose term expires in June 1985, said she had no idea who her successor might be. Although Mrs. Thomas is a conservative Democrat, her views on the commission, particularly on budgetary issues, have at times been at odds with the conservatives appointed by the Reagan Administration.