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Even babies know what's fair, new study shows

There’s no better time than Halloween to see a kid’s sharply-honed sense of fairness. This is particularly clear when you have more than one child.In our house, the post trick-or-treating ritual of sorting and counting candy nearly always results in a battle because Big Sis procures more candy than Little Bro. Which results in whining by LB. After plenty of parental refereeing, BS, magnanimo

There’s no better time than Halloween to see a kid’s sharply-honed sense of fairness. This is particularly clear when you have more than one child.

In our house, the post trick-or-treating ritual of sorting and counting candy nearly always results in a battle because Big Sis procures more candy than Little Bro. Which results in whining by LB. After plenty of parental refereeing, BS, magnanimously, gives LB a few handfuls to even the score (never mind that it’s mostly candy she dislikes).

Kids get the concept of fairness pretty early on. Now, new research shows that children understand a basic sense of fairness and altruism even younger than once thought.

The study found that babies as young as 15 months understood the difference between amounts of food. What's more, how they feel about "unfairness" is linked to their willingness to share a toy, according to Jessica Sommerville, a University of Washington associate professor of psychology who led the research.

First, the babies sat on a parent’s lap and watched videos showing people sharing food. In one a bowl of crackers was split (first evenly, then unevenly) among two people. In another a pitcher of milk was split the same way. Researchers recorded how much time the babies spent looking at each scenario, which is a way to measure their interest.

In the second part of the experiment, the babies could choose between toys: a simple LEGO block or a more elaborate LEGO doll. Whichever toy chosen was considered the baby’s preferred toy.

Then, a researcher gestured to the toy and asked the baby, “Can I have one?” One third of the babies shared their favorite toy, while another third shared their unpreferred toy. (The last third didn't share either toy -- tough luck, researchers!)

“The results of the sharing experiment show that early in life there are individual differences in altruism,” Sommerville said.

When the two experiments were compared, researchers found that the babies who spent more time looking at the unequal servings of food -- who were surprised by the unfairness -- were far more likely to share their preferred toy. In contrast, the babies who looked longer at the fair division of food were more likely to hand over their less-preferred toy. Researchers classified the first group as "altruistic sharers" and the second group as "selfish sharers."

“The altruistic sharers were really sensitive to the violation of fairness in the food task,” Sommerville said.

Perhaps the "selfish sharers" were just graduates of the school of hard knocks -- at 15 months, they've determined the world is an unfair place, so they're going to hang on to their toys at all costs. Or perhaps they were just cranky and needed a nap. Hopefully we parents have something to do with what sort of sharer our kids turn out to be.

All I know is, this Halloween we're not going to get involved in the kids' candy counting.  They can work it out themselves, since clearly they've had plenty of time to hone their fairness skills.

Kavita Varma-White is a writer, editor and mom of two tweens. In between cheering at numerous soccer and baseball games, she's a contributing editor for TODAY Moms and MSNBC.com.