12/18/2014 12:15 pm ET Updated Dec 18, 2014

Science Explains Why Kids Are Terrible At Sharing

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When we were kids, sharing our snacks or toys was about as appealing as sitting in time out. We were hardly willing to give up our most prized possessions to our peers right away -- and now neuroscience might be able to explain why.

According to a new study, it takes more of a controlled thought process for kids to be generous. While children have an immediate, emotional response in the brain when they witness positive or negative behavior, deciding to share something comes after evaluating the whole picture and reflecting on the morality of those actions.

"Moral evaluation in preschool children, similar to adults, is complex and constructed from both emotion and cognition," study author Jean Decety said in a statement. "However, we found that only differences in neural markers of the latter predict actual generosity."

Researchers from the University of Chicago recorded brain activity of children ages 3 to 5 while they viewed helpful and harmful scenarios, and then had to make a decision on how to treat another child they didn't know.

The children were gifted 10 stickers, then were told the next child who came into the room wouldn't be given any stickers. Researchers then asked if they wanted to give any of their stickers to the other child. The kids shared a little under two of their allotted 10 stickers on average.

The research suggests that the children's judgments were influenced immediately by the harmful and helpful scenes they were shown, but they only chose to be generous after thoughtful processing of those scenes. The study is the first one of its kind to link immediate moral evaluations to actual moral behavior and the specific markers where it happens in the brain, researchers say.

In a time of the year where acts of altruism are so prevalent, the study authors suggest the findings could help parents who are looking to help instill the values of giving in their kids. Previous research also shows that giving back can have a host of health benefits, including lower stress, a happier disposition and even increased longevity.

The findings were published in the journal Current Biology.