Preschoolers don't care how hard they worked to win a prize. If it's a lame reward, it's likely to go in the garbage. But with age, research shows, kids learn to appreciate the work an uninspiring prize symbolizes.

To value a prize, not for the prize itself, but for the work it took to receive, may seem like behavior that requires maturity. But new research suggests children as young as 6 are less likely to give up relatively crummy prizes if they were earned with hard work. Four-year-olds, on the other hand, have little time for lame prizes -- hard work or not.

"When effort leads to an unsatisfying reward, adults experience a cognitive dissonance, arguably resolved by reappraising the reward's value," study author Avi Benozio, a psychological research scientist with Israel's Bar-Ilan University, said in a press release.

"We found this dissonance to occur already among 4- and 6-year-olds," continued Benozio. "Whereas 6-year-olds reduced the dissonance by keeping their rewards and boosting its value afterwards, 4-year-olds took quite a different approach and detached themselves from the source of the discomfort by getting rid of the unsatisfying rewards."

To study the role of rewards, and how they are valued by young people, researchers divided young children into groups and had them participate in what they called the sticker game.

First, participants played a game to earn their stickers. Next, the participants -- now in possession of an array of stickers (some of value, some less so) -- were asked how many stickers they wished to give away to a child featured in a short video.

The rub was: not all kids earned their stickers equally. Groups were randomly assigned to play either a difficult sticker game or an easy one. Kids in the hard group were asked to complete tasks like "count as high as you can," while kids in the easy group were given easy tasks like "say your name."

Researchers found that 6-year-olds who completed harder tasks were less likely to give away even the ugly stickers than were their peers from the easy group. Oddly, 4-year-olds from the difficult group were even more likely to give away ugly stickers.

"The relationship between people and their 'stuff' is intriguing but the subjective value children attribute to resources has been somewhat overlooked," added Benozio. "Our research suggests that behaviors that appear to benefit another person -- such as sharing stickers -- may actually stem from the relationship that a child has with that object, regardless any potential beneficiary."

The new research was published in the journal Psychological Science.