Most of us know that children are not miniature adults. But that doesn't answer the main question: Who are they? How do they look upon this world, so familiar to us and so new and strange to them? In its first few months, the human mind takes on more basic information than it will learn all the rest of its life. What is it like to be so bombarded by experiences? We visit some small children making their first contact with the outside world, their debut in society.

They are both about 3. Blond, gray-eyed, in a jumper with ducks on it, she is riding a tiny tricycle in the carpeted corridor of Rosemount Center. This is her first day. He has dark curly hair and a scowl.

He grabs the handlebars.She pulls away. He moves in, eyes bulging, mouth pulled down, chin tucked into chest because that is the way his father looks when he comes after him.

She doesn't seem to know what the rage-face means. Equably but firmly, she turns the trike and pedals off. All at once his face changes. You can't see his father there anymore, only a bewildered small boy deciding whether to cry.

Veteran Rosemount teacher Jose Rivera has set up a Getting It Together Corner in the Chickadees' room. It is just a little chair in the corner behind the door.

"It's not punishment," he said. "When kids get to aggressive I put 'em there to get themselves together for a while. If you punish kids they just become more rebellious. At the same time I ask 'em what's wrong. We work it out."

Rivera is a rarity, a man who works with the children in a day-care center. Usually, male day-care workers climb, or are pushed, into administrative jobs. But Rivera stays with the Canaries, Ducklings and Chickadees on the first floor of the center, the mostly under-3's.

At 38, he is the head teacher of this group. He makes about $7,000. It took him seven years to reach that point.

A Puerto Rican raised in New York, he made good money in the construction business, but he came here because he has a gift for children. They flock to him. They always have. He can put his hand on the head of a fretting child, and the fussing stops instantly.

He wants to work upstairs, with the Gatitos (little cats) and other older ones -- the center takes children through 5 -- but he would have to start at $6,000, and he couldn't become the head teacher there anyway because he doesn't have a college degree.

Now he is doing picture puzzles with Johnny, an exceptionally bright 2-year-old. There are six pieces in the puzzle, and it goes slowly.

"You're looking for the bird? Where's the bird? Does it look like that one?"

"I learned a lot from these kids," he said. "They taught me patience. I learned how to deal with adults much better. At one time I had a fighting temper, a chip on my shoulder, a grudge against society."

Another boy bursts into the room, looking for him. Rivera firmly steers him out."

"I'm sorry, you have to leave, Gene. I'm sorry. Be with you in a minute."

Gene goes away without much complaint. A few months ago he would have thrown a tantrum.

"I don't call kids bad. They're just active. Now with Gene it hasn't always been that easy. It took a lot of holding."

He is concerned with the silent ones who sit on the fringes of the joyously chaotic activity.

"They're in their own world, you know. The trick is to get into that world with 'em and slowly bring 'em out. With games and things. But sometimes you have to leave them. If you take them out, you strip them bare, and it's the only thing they have going."

He knows all the puzzles. He can recite every children's book in the place by heart.

"Oyez Oyez! O Rah Rah! Companeros muy grandes! Companeros unidos!"

-- Chanted at the top of their lungs by a dancing chain of 3-year-olds led by a tall black man who has to stoop to hold the nearest hand.

Rosemount is a Spanish-influenced, gray stucco mansion built in 1882 by the Episcopal Church and used until eight years ago as a home for unwed mothers. It switched because the need for cloistering "girls in trouble" faded out with the change in American mores.

Meanwhile, the need for day care for the children of working mothers was becoming a national problem.

Day care, as director Louis Sullivan says, is a way of life in this country today.

The government, federal and city, has yet to discover it, she adds. She and board president Julia Morgan have been haunting City Hall recently to fight fund cutbacks.

"The city is cutting 628 slots in its day-care program," said Julia Morgan. "Slots -- that's their word for children. They figure it will save $400,000, and they're putting the $400,000 into welfare."

An ironic smile. "They'll need it in welfare. Because the minute you cut a child out of here, it means the mother can no longer work. So she goes on welfare."

The D.C. Department of Human Services also has decreed that a 2-year-old is not an infant but a preschooler.

The city pays only about 60 percent as much for a preschooler as for an infant.

"DHS wants them to stop being infants on the very day they turn 2. In fact, the city has a hard time understanding why they don't all become 2 on the same day."

Of course, the center will not blindly shunt kids up to the advanced groups of their second birthdays but will continue to keep them in the infant center until they're ready to move up, usually around age 3. It will simply take a loss of income and try to cope with the problems of instant toliet training. Presently the public funding comes to $62.50 a week per child, averaging all ages, as against the $63.78 it cost the center. Cost for infant care is $21 a day. There is some private money. Tuition ranges from nothing to $75 a week.

"We had a new 2-year-old in the upper room this morning," said infant-center coordinator Linda Ohmans. "He was disrupting the whole place. He couldn't even cross his legs, and another child was trying to teach him how to cross his legs. He's just a baby still."

"My father, he don't come home. He come at Christmas. We had pancakes for Christmas. Hey, what you get for Christmas?"

-- 5-year-old.

"There's a new pattern today," says Julia Morgan. "Young wives say they'll stay home and be mothers for a stated time, say three years. So they have two children very close together. Which means the older one never gets that experience of having a baby sister or brother. They get very little idea of mothering. And the extended family is dead."

For growing numbers of American children today, the day-care center is a life style. Resulting from the demise of the extended family with its live-in baby sitters and the rise of the working mother, these centers are expanding children's horizons much earlier than ever before, making them social creatures long before they enter kindergarten. They are different from what their parents were like as children; will they be different as adults? So much depends on the day-care center itself.

Rosemount, located in the Mount Pleasant area, is considering a model day-care center. With 108 children in the building and another 26 placed in city-funded satellite homes, it has a waiting list as long as your arm.

One reason for the appeal is its mix. It is multiracial and bilingual. All the signs in the halls are in English and Spanish, and the children, are encouraged to pick up each other's languages.

"It's very structured," one mother observed. "It may not look like it, with everyone swinging from the chandeliers and all, but it's really very orderly. It gives them a sense of security."

The walls are covered with animal pictures and thing pictures: a gorilla, a spoon, crayons, a cat. And artworks by the children themselves, the classic spiky sun, the house with smoking chimney, the unnamable but threatening animal, the people with eyes high on their foreheads (because that's how they look to you if you're three feet tall), always signed with eclat, Liam, Anna, Lilia -- this is something that never changes from one generation to another.

The rooms have Dutch doors. Inside are small chairs and low tables and playhouses with holes and chutes for climbing in. One was built by a father. In a corner are several round pads forming a ring on the floor, each with a name on it.

"They love to have their own things, their own special places," said Ohmans. "It gives them a sense of identity and safety.

Lining the corridors are little open lockers, each topped by a plastic basket with a child's photograph on it. The children gravitate to these lockers, perhaps pulling out jacket and hat and putting them on, perhaps picking up a doll that resides there. It seems to make them feel grown-up to have possessions.

(The jackets are nylon, with mittens attached to the cuffs. It's not the way it used to be, an elastic running from one mitten up the sleeve, across the back and down to the other. These days they have clips that join mitten and cuff.)

From time to time kids roll on the Snoopy mattress on the floor. Sometimes they tumble like kittens together, not quite paying attention to each other. Sometimes they just lie down a moment, thumb in mouth.

One room is for babies in cribs. Another is for creepers, with chickie-yellow curtains and a jungle gym. A third is for toddlers ("There's something about the room that makes them act older," Ohmans said.) Upstairs, the rooms are noisier. The emphasis here is on activities and cognitive development, a teacher said, though there is still a good deal of mothering.

"It's flowers time. I like to do the numbers. This is a Red day."

-- 3-year-old who is learning the calendar by colored numbers.

Four 4-year-olds are packed into a boat-shaped rocker, industriously rocking while a teacher sings a boat song somewhat superfluously. A fifth tries to get aboard. The teacher suggests that he wait till next time, but he circles, frowning in his concentration finds an opening on a thwart, squeezes between two peers and starts rocking. He doesn't seem paticularly triumphant. It's just that he had to be there, right then.

In another wing is the Special Needs Room. Here a handful of children spend part of the day getting extra loving on a one-to-one basis from trained child therapists and others. These children aren't able to adjust to the hurly-burly of the center, the social situation, as the teachers say, but in the afternoon they are encouraged to join the others. The center is trying to get money from the United Way to help staff this room. There is already some funding from the city.

On the floor, a little girl is being comforted by a volunteer in a tight embrace. Small fists are enveloped by large palms. A silent little boy looks up from his game, and another invites the visitors to come to his corner. l

"A few months ago he couldn't have done that," Louise Sullivan remarks. "He was really cut off."

"Oh, I like to play. I like to play with worms.I put them in my pocket and they get dead."

-- ("How old are you?" Four fingers pop up, palm forward. The worm is safe in the other hand.)

Some of the children use abusive language in a way that hints at tempestuous troubles at home, she says.

Sign on the wall: "When you use those words I know you aren't feeling good about yourself."

"The longer they're here, the more they learn about getting along with others," says Jeanette Jones. Herself the mother of four, she has been a staffer at the center since its unwed-mother days. "Some parents are uptight and expect their child to be treated like the only one here. You have to treat all parents the same. The kids you treat according to what they need."

One mother, who has sent all three of her daughters to Rosemount, sees nice things happeining in their growing up.

Since she works part-time, they would spend five to six hours a day at the center. The youngest, 2, has been lodged at a satellite home, presided over by Mrs. Marie Lynch until her recent death from cancer.

"Alison grew up in Marie's house. She went there at 5 months. It was all a big family: the three others from the center, Marie's own older children, cousins, a grandmother, always people coming and going.

"Alison never cried in that house. She'd go out and help pick tomatoes in the garden, she'd help bake the Christmas cookies, there was always some celebration going on there. It was part of her life.

"And Marie, who was a Guyanan, a big, comfortable woman, would be going around with a baby balanced on her hip, talking on the phone, relaxed and easy. I felt a distant relative myself. She was 42 when she died."

The three girls picked up some odds and ends of Spanish at Rosemount. Pinatas are now part of the family culture, their Australian-born mother chuckled. ("I go nuts making them every birthday.") They learned to help with the meals, proud to be part of the adult world, and they are thoroughly colorblind, she said.

"Socially, they're far ahead of other kids when they go to kindergarten. One has moved up a grade already. They're ready to start work the first day, while some of their peers are still learning how to get along."

She feels the Latin influence, with its emphasis on big extended families and its tradition of motherly caring, is important for the upwardly mobile Rosemount families and one-parent households.

"It's beautiful to give love to difficult kids," says Jose Rivera, "but you have to remember that love also includes letting them know when they're out of line. Love is an entire circle.

"The reason I'm not fazed at what people think of my works is that I had a very loving family. I always had that inner strength. What I like to see is other men coming into this work. Every summer we have student helpers, and it's always teen-age girls, but lately the boys have been coming too. That's good. That's what we need in this world."