(Photo: Amanda Tipton/Flickr)

"I hate my job, but it pays the bills." "He comes off like a jerk, but really he's a good guy." Adults are good rationalizers, able to make lemonade out of the sourest lemons. But it seems it's not just grown-ups: A new study suggests we develop that skill sometime between ages four and six.

Rationalizing is just one example of what's called cognitive dissonance reduction, a kind of mental gymnastics that reduces the anxiety of inconsistent beliefs and actions. For example, a smoker confronted with the health risks of smoking could resolve the resulting anxiety either cognitively or behaviorally—that is, by downplaying the risks, or by quitting cigarettes. Yet there's something funny about that: Most people, most of the time, go the cognitive route, and it's not entirely clear why.

"One possible reason ... is that adults are quite proficient at altering" their opinions and beliefs, write psychologists Avi Benozio and Gil Diesendruck. And if we adults are particularly adept at justifying our choices by adjusting the truth, that suggests rationalization is a skill we pick up some time in childhood.

Older kids gave away fewer stickers when they'd had to work for them, suggesting the more effort required, the higher value they attributed to the task.

To test their idea, Benozio and Diesendruck asked 45 three- and four-year-olds and 53 five- and six-year-olds to complete a series of assignments in exchange for stickers. Some tasks were easy—telling researchers how old they were, for example—while others were more difficult. In one task, kids were asked to close their eyes and count as high as they could, and were then challenged to count five higher than that. Unbeknownst to the children, completing the harder task didn't necessarily mean they'd get the stickers they liked—maybe it'd be Dragon Ball stickers, or maybe it'd be Disney princesses.

Finally, kids had the choice to give some of their stickers away to another child, a test that revealed how much they valued their stickers. Regardless of their stickers' intrinsic appeal, the researchers found that older kids gave away fewer stickers when they'd had to work for them, suggesting the more effort required, the higher value they attributed to the task, just as adults have acted in previous experiments. Younger children, however, gave away the same portion of appealing stickers when they'd worked for them as when they hadn't, and they actually gave away more of the unappealing stickers—the ones they'd worked for—than those they'd acquired with ease.

These results suggest that younger children resolve the dissonance of working hard for yucky stickers behaviorally—by giving them away—but by around age six, kids start to rationalize by favorably re-evaluating the rewards of their misspent efforts, a distinctly cognitive approach to reducing dissonance and anxiety.

The mental-health benefits of rationalization aside, Benozio and Diesendruck write, it's often better to change one's behavior, as is the case with smoking. "In this regard, four-year-olds’ ... greater difficulty in recurring to cognitive maneuvers of value representations, may have served them—and may possibly serve adults—well," they write.

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