Today is Jan. 1, a day when people celebrate the beginning of a new year. On New Year's Day, people feel like they're getting a fresh start. You've probably noticed that the cards and decorations used at this time of year often show an old, old man with a long beard, along with a brand new baby. The elderly man stands for the old year that has just ended. The baby stands for the new year that's just getting started.

This morning there may be a story in the newspaper or on television about the very first baby born in 1986. At hospitals around the country, newborns who arrive at 12:01 in the morning get special attention. People are happy to celebrate the birth of a brand new baby for a brand new year.

A baby is a good symbol for a new beginning. Even mothers who have lots of kids feel excited about each new baby. Even though infants won't do much more than eat and sleep at first -- and newborns may sleep 23 out of 24 hours -- being around them can make older people feel hopeful about the future.

If you have a new baby in your house, you probably already know a lot about how they behave. You know that babies are interesting, even when they're sleeping. While they may not seem to be very active in the first few months of life, they are actually busy growing and learning from the very beginning.

Newborn babies are completely dependent on other people for survival. At birth, human beings can't sit up, talk, walk or feed themselves. During the first month of life a baby's neck muscles aren't strong enough to support its head. That's why you have to support the head very carefully when picking up or holding a newborn. The only way babies can let others know what they need is by crying.

But babies very quickly learn to do things on their own. During the second month of life, babies begin to develop motor skills. These are the ability to control movement -- like turning the head from side to side, or reaching a hand out to grab something. By the time a baby is about 5 or 6 months old, it can turn over in bed. Parents get very excited the first time a baby turns over in its crib by itself. Ask your mother and father about the first time you did it. They'll probably be able to tell you exactly when and how it happened.

By the time babies are toddlers, at around 18 months, they can walk and run, laugh and play, get angry, feed themselves, and even say a few words and phrases. They have done an amazing amount of learning and growing in a very short time.

So much goes on during infancy that many scientists spend their whole careers studying one small part of it. Some researchers study how babies learn language. Others focus on what a baby's facial expressions show about how it's feeling. Others concentrate on how babies learn to use walk. Some researchers are interested in the kinds of relationships babies have with the people around them.

Babies begin to notice other people, and interact with them, very early. Next time you meet a 3-month-old, try smiling at it. Once the baby is used to you, it may smile back. Getting a baby to smile is a great feeling.

One thing researchers have proved beyond a shadow of a doubt is that babies need to be touched. Of course they also need to be fed, clothes, and kept warm and clean. But they also need to be loved. Cuddling a baby makes an adult feel good -- but for the infant it's even more important. Some scientific research suggests that babies who experience a lot of physical affection grow up to be happier, healthier people than babies who don't get much hugging.

Is there a baby in your life? Today would be a good day to cuddle it for a while. You'll be doing your part to help the baby have a healthy and happy 1986. Tips for Parents

For many youngsters, baby-sitting offers a chance to interact with infants, and learn about how human beings develop. The nursing and health services division of the American Red Cross has developed a curriculum to help young people learn how to be informed, compassionate baby sitters on whom parents can rely. The eight-hour course teaches sitters how to care for children physically, how to avoid dangerous situations and how to administer emergency first aid. Students are also instructed in basic child development. For more information, contact your local chapter of the Red Cross, or the national office at 17th and D streets NW, Washington, D.C. 20006; 737-8300.