THE EVIDENCE keeps suggesting that the present recession has moved far from the established pattern of the past several decades. The sales of American-made automobiles in February, according to the tabulations that appeared yesterday, were the lowest in 20 years--just as last month's and, for that matter, last year's sales were also the lowest in 20 years. The February sales were 16 percent below those of the same month a year earlier.

The recession seems to be coming on top of a longer decline in the automobile industry and the other industries that depend upon its health--steel, glass, rubber. A recession is a cycle, and each decline, however painful, has always been followed by a swing upward that brings the economy back to its previous peak and higher. But it's pretty clear that the automobile companies aren't merely going through another conventional cycle. The long upward trend in automobile production seems to have reversed direction sometime in the late 1970s, and is now wandering downward. The reasons may turn out to lie a good deal deeper than simply the reduced amounts of money that people have available to spend. Perhaps part of the explanation lies in changed tastes and choices.

>From the late 1940s to the late 1970s, Americans greatly increased the proportion of their total spending that went into automobiles. Over that span, as they got more prosperous, they sharply reduced the shares of their personal budgets that went into food and clothing. Where did the money go? Mainly into three things --houses, medical care and, of course, cars.

It's beginning to look as though a lot of people have now decided not only that they want smaller and more efficient cars, but that they also want to spend less money on transportation. If that turns out to be the case, the outlook for the auto makers becomes more somber than ever--and not only for the auto makers. Over the past decade, they have begun to produce a wide variety of small cars with good fuel efficiency. But, as you may have noticed, those little cars are not cheap--in relation either to the big cars of the 1960s or to the imports.

If American attitudes about cars have in fact shifted--in one of those great silent turns of collective opinion, visible only in restrospect, that underlie economic history--the implications for the whole economy are enormous. It means fewer companies in the business, employing far fewer people, generating less wealth. That is not a description of a recession. That is a much more serious matter, from which the recession is only distracting the attention that it requires. It is irreversible structural change, with a vengeance.