Your Kid's Brain On Santa Claus : Shots - Health News At what age does a kid's belief in Santa peak? Psychologically speaking, the answer is 5, when young brains are full of imagination and not so much doubt.

Your Kid's Brain On Santa Claus

Spoiler Alert: We're not sure how many 5-year-olds are fans of Shots, but if you're impatiently waiting for a jolly old man dressed in red to drop off your Christmas presents, please stop reading now.

Shh...Santa's not real, but how does your brain know? hide caption

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Shh...Santa's not real, but how does your brain know?

So if you're still with us, we assume you already know that Santa isn't real. But how and when did you figure that out? Chances are it was probably some time after age 5, the peak age for believing in Santa, psychologically speaking, according to a recent study described in the Wall Street Journal.

As children's brains develop, so do their reasoning skills and imaginations. Those are important ingredients in a child's belief system. To a kid, believe it or not, Santa has a lot in common with real figures like the garbage man, according to one researcher of "magical thinking," Dr. Jacqueline Woolley, a psychologist at the University of Texas, Austin.

Kids hear about both those "people" from authority figures and see evidence that they exist. The trash disappears each week into a big truck, and once a year they wake up to presents under a Christmas tree. But they probably don't ever see those people, which got Woolley wondering why kids believe consistently that the garbage man is "real" but their belief in Santa builds between ages 3 and 5, before declining between 6 and 9.

The difference is that the evidence of Santa--gifts under the tree, bites out of the cookie, full stockings--is a ploy. Parents and society give kids false evidence that a cheery fat man drives around a sleigh all night and delivers presents to all the nice kids in the world. You and I can understand that logically this evidence doesn't sound feasible, but for a 5-year-old everything in the brain is lining up just right for Santa to seem perfectly real.

Kids younger than 5 don't have the cognitive ability just yet to really put together those pieces of "evidence" that Santa is real. But at 5, they have just enough to add up what society and their parents are telling them, but not enough to doubt it or look for contrary evidence.

When kids get older though, if they wake up in the middle of the night and find their mom putting presents under the tree, they have the ability to doubt their previous notion that Santa was real. That's probably why Woolley and her colleagues saw a sharp decline in the number of kids who believe in Santa between ages 6 and 8.

But it also depends on outside influences that drive them to look for that negative evidence, Woolley told us. She's a mother of two, and her 12-year-old daughter stopped believing in Santa only a year ago, when mom the psychologist stopped trying so hard to convince her.

Two Christmases ago the daughter's doubts were growing, so, taking after her mom, she set up an experiment. She left a camera on a table with a note telling Santa to take a picture of himself if he was real. Woolley played along that year, writing back that Santa couldn't figure out the buttons on the camera, but by last year she stopped being so careful and let her daughter see the "Santa presents" being put under the tree.

Maybe it's because we're surrounded by bah-humbuggers, but Woolley's work got us wondering how long kids believe in the Grinch? She didn't miss a beat, answering, "the Grinch is different." He's only introduced in a fictional context, plus he's a negative fantastical being, like a witch or a monster, which kids are less likely to believe in anyway. "He lacks a lot of the advantages that Santa Claus has," said Woolley.

What is it about Christmas that makes it such ripe fodder for psychoanalysis? (All that magic and mysticism? Or maybe too much family and the accompanying neuroses?) You name it, and someone has studied it. For some festive, seasonally appropriate research on gift-giving, Christmas smells and even what makes a "happy" Christmas, check out this great compilation of The 12 Psychology Studies of Christmas, from Psyblog.