Each year at about this time parents everywhere face a familiar question: what to do about the sweet myth of Saint Nick? Should they encourage their children's joyous belief in Santa Claus and the openhanded love he represents? Or is such well-intentioned deception harmful, possibly creating a painful psychological scar?

Dr. Carl Anderson, 34, is a man uniquely qualified to answer such worries. A blond, bearded therapist with bright blue eyes and rosy round cheeks, Anderson answered a shopping mall management company's ad that read: "Wanted: Eyes—twinkle. Dimples—merry. Cheeks—rosy. Beard—snow." Since then, he estimates that he has bounced some 15,000 kids on his knee. The experience inspired his dissertation, "On Discovering the Truth: Children's Reactions to the Reality of the Santa Claus Myth," which earned him a Ph.D. in counseling psychology from the University of Texas.

Born in New Jersey, but raised in Florida and Texas, Anderson has never had a white Christmas. "My Christmases have all been in shorts and shirtsleeves," he says. A bachelor living in Austin, Anderson spoke with National Correspondent Lois Armstrong about playing Santa and what he has learned about children's reactions to learning the truth about Mr. Claus.

How do children react to you as Santa?

I was immediately impressed with the intensity of their belief. Sometimes they get too excited; they get up to Santa, and they can't say anything. They go into what I call "Santa shock." Sometimes they cry. The child thinks he's being left with this larger-than-life cartoon stranger. I have a lot of respect for parents who don't force their kids to visit with Santa.

What do kids tell Santa Claus?

Kids will say anything to Santa. The very first child who sat on my lap was a 5-year-old boy who looked up at me and said, "I guess my daddy doesn't love us, because he left home." I suddenly knew that this was not going to be just "Ho, ho, ho, what would you like for Christmas?"

What kind of survey did you conduct to explore children's reactions to discovering Santa is a myth?

The subject sample consisted of in-depth interviews with 75 children, age 9 through 12, and their mothers. They were drawn from summer day-camp programs run by the Austin parks and recreation department. We used only children whose parents were certain that the kids no longer believed in Santa Claus. Children were interviewed personally and parents were given questionnaires to fill out. I didn't do any of the interviewing at all for fear of biasing the children because of how I look.

What were some of your findings?

The major surprise to me was that children reported having a more positive reaction, rather than a negative one, to the discovery and acceptance of the truth. More of them [62 percent] felt glad about learning there is no Santa Claus than sad or disappointed. The good feelings seemed related to a sense of pride in having figured out the truth. The children felt more grown-up and were now siding with parents in upholding the myth for younger siblings. There was also some relief at having the issue resolved because they'd usually been wondering about it for some time.

How do children find out the truth?

It appears to be a gradual process. The majority go from belief to doubt to disbelief over a couple of Christmases, when they begin to realize that certain things are illogical: A fat man can't come down a chimney, reindeer can't fly, and Santa can't get around the whole world in one night. When they're ready, children make a decision to no longer believe. That's why they don't get as upset as we're afraid they will. A number continue to pretend to believe so as not to spoil the fun for parents.

Don't some kids have negative reactions?

The ones who experience more negative reactions are often girls who found out at a younger age than most children and who were inclined to be very involved in fantasy and make-believe. One girl said, "It felt good to know that there was somebody somewhere who cared so much for kids that he would do this." With that belief gone, it was more of a blow.

What effect does the discovery by the children have on the parents?

The most frequently mentioned parental response was sadness. The discovery was an indication that the child was growing up, and it was happening too fast.

Would you teach your own kids to believe in Santa Claus?

Definitely. In fact I think I would be one of those parents who overdoes it. I've talked to parents who have put footprints on the carpet next to the chimney, others who actually get up on the roof and pretend the sleigh has landed. I have one friend with twin boys who put on a Santa suit one year and ran alongside the fence of the dimly lit backyard with sleigh bells and a pack over his back. Now he's worried because the boys are 10 and still maintaining that Santa is real because they saw him with their own eyes.

How do you suggest parents present the Santa myth, to lessen the blow of discovering the truth?

It's important not to overemphasize the belief, especially if the child is prone to be very involved with make-believe and fantasy. What's nice is for the family to develop its own tradition and stick to it. And don't overprotect the belief. Some parents, when the child starts acknowledging doubts, do whatever they can to keep the child from disbelieving.

How should parents handle the situation when a child is clearly on the verge of finding out the truth?

Parents need to allow the child to accept the truth when the child wants to. It's a hard thing to gauge because sometimes the kid may come to them and ask, "Johnny says Santa's not real—is he telling the truth?" Find out why the child wants to know. Sometimes the child might be asking for continued permission to believe, some reassurance that the belief can be maintained. Get a sense of whether or not the child has figured it out.

What then?

Once the child knows the truth and lets the parent know he knows, it's a good idea to discuss why the parents promoted the belief in the first place. Help the child recognize that this is something that is common to all children. Also, encourage children to talk about their reactions and express their feelings.

On the whole, then, you think believing in Santa is good for children?

We asked the kids why they think they're taught to believe in Santa. Very few [8 percent] said it was so they'd be good. Exactly half felt that it was so they could enjoy themselves at Christmas, and they thought it was an important tradition to pass on from generation to generation. One called Santa "the mascot for Christmas." An 11-year-old boy gave a serious explanation that parents could certainly understand. He wrote, "Maybe because the world we live in is so bad...we have people killing people, people take hostages...all kinds of accidents are happening all over the world, that Chernobyl thing and all that stuff...so Santa is a nice thing in a cruel world."