A Christmas spoiler warning - don't let your children read any further.
An article in international journal New Scientist this week grapples with the sticky issue of whether the Santa myth damages children.
"Adults often stage elaborate deceptions, laying traps for the children's developing intellect," Tom Flynn, a secular magazine editor, told the journal. It was unfair to trick children and leave "evidence" such as empty glasses of milk. Parents could threaten children with punishment from Santa if they misbehaved - promoting "unhealthy fear" - and the myth could make children more selfish and materialistic, he said.
University of Texas psychologist Jacqueline Woolley said children had a better grip on fantasy and reality than many people realised.
But they relied on adults to provide them with reliable information about the world. Friends, books, movies and "hard evidence" of Santa planted by their parents reinforced the myth. "Children do a great job of scientifically evaluating Santa, and adults do a great job of duping them."
Educational psychologist Carl Anderson, also of the University of Texas, interviewed 52 children who no longer believed in Santa. He said they generally discovered the truth on their own at the age of seven, despite "very strong" parental encouragement to believe.
In New Zealand, Otago University senior psychology lecturer Tamar Murachver said one of the main concerns parents had was that lying could undermine a child's trust in them. But the Santa myth was embedded in culture, so it was society telling the lie rather than parents. "I don't actually see that it's undermining trust."
She suspected her own eight-year-old son had now twigged.
"I'm absolutely sure he knows the truth about Santa but he doesn't really want to say it because what if we don't have Christmas?
"Children eventually discover for themselves the distinctions between fact and fiction. For the most part, even today's critical thinkers once believed in Santa Claus."
New Zealand Skeptics also gave Santa the all-clear. "It would be a hard-hearted parent indeed who frowned upon the innocent joys of our children's cultural heritage," spokeswoman Vicki Hyde said.
"We save our bah humbugs for the things that exploit the vulnerable."
Her own children had been sceptical. "They figured it out for themselves when they saw that every mall had its own Santa, complete with commercial photo operation."
- The Dominion Post