When the advertising industry gets serious about selling products to black America, it discovers that old racial stereotypes perish in the marketplace.

The Leo Burnett agency of Chicago commissioned extensive research on the lifestyles of black consumers and learned there are important differences with whites.

For instance:

Black women care more the neatness of their homes than white women do. Thus, they are a stronger market for household cleaning products.

Black women, despite their frustrations and disappointments, are more nostalgic than white women about the past. They care more about scattered relatives in distant parts of the country. They buy more of the so-called "keep-in-touch" products - greeting cards, stationery, snapshot cameras, film.

Black women have stronger career ambitions. But they are also more frustrated by their jobs, having been "liberated" from the sole role of housewife long before it became fashionable among middle-class white women. As working mothers with less time for cooking, black women buy more convenience foods, frozen pastry, canned stew, refrigerated cookies and biscuit dough.

Black women are more budget-conscious. Their family incomes are generally lower. Grocery shopping means studying the weekly ads for "specials" and watching for sales.

These dimensions of black life styles are drawn from a national study in which Leo Burnett examined 200 areas of activities, interests and opinions, summarized under a ten-dollar title: "Psychographics of the Black Consumer."

In most areas, white and black women are alike. But the cross-cultural differences may be crucial to an advertising campaign aimed at blacks. Joseph T. Plummer, who directed the research, said advertisers are just beginning to grasp this.

For instance, advertising that coyly exploits women's liberation themes might communicate with white women while it offends black women.Work is a necessity, more often, for black women. While they have made significant gains in the labor market over the last 15 years, their frustrations are high. So are their hopes.

Here are some contrasting white/black attitudes from the Leo Burnett study of women:

In a job, security is more important than money: white 36 percent/black 53 percent.

A full-time job keeps a woman feeling younger, happier, more with today's world: white 35/black 54.

I really want a career: white 26/black 57.

My greatest achievements still lie ahead: white 37/black 51.

Our income is satisfactory: white 48/black 27.

If I had my life to live over, I'd do things differently: white 36/black 58.

At home, black women typically do less baking and depend more on precooked convenience foods, according to purchasing indexes compiled in the study. They plan meals ahead more frequently because competing schedules often keep their families apart at mealtime. Two-thirds of the white women said their families eat together every day, compared with one-third of the black women.

Purchasing patterns confirm what black women say about themselves in the attitude survey - they care more about the neatness of their homes, perhaps because they more often live in grimy and old inner-city neighborhoods. Black women have much higher pruchasing indexes for rug shampoo, oven cleaner, air freshener, insecticides, plastic trash bags aw well as personal cleanliness products such as facial tissue, paper napkins, beauty soap and mouthwash. They feel more strongly about pollution.

I get satisfaction out of cleaning because that is what people notice: white 29/black 46.

A house should be dusted and polished at least three times a week: white 28/black 41.

I like ultra-modern style furniture: white 14/black 34.

Black women's hopes and fears are shaped by urban life."I can always count on my neighbors for help," say 58 percent of the white women but only 36 percent of the black. More than half of the black women said: "I have few close friends."

But black women express a stronger desire for a sense of community and nostalgia for the simpler life of the past. The advertising study said this feeling may be rooted in the great migration that so many black families experienced from the rural South to the urban North during the last 40 years.

This would explain the higher purchasing index for the "keep-in-touch" products. The typical black family in the North has kinfolk in the South with whom it corresponds.

I often wish for the good ol' days: white 28/black 41.

Plummer explained:

"Many have achieved the things they sought, yet the transition for some has fostered new problems. The sense of 'community life' characteristic of the South has been altered by overcrowded conditions in urban areas. The open space of rural towns has been replaced by the concrete structures and pollution from factories in neighboring inner-city areas. Visiting friends in the evening is overshadowed with risks of vandalism and assault."