Young children may believe in Santa Claus and the Tooth Fairy, but they are more savvy than many adults may think, according to a new study.

In two experiments with children in kindergarten and elementary school, researchers at Yale University in New Haven, Connecticut found that while young children are indeed more gullible than older children and adults, they may already have signs of cynicism by the time they are in second grade.

In fact, the study authors found, young children may be more cynical than adults in certain respects.

Young children usually interpret a misstatement as an outright lie, while older kids and adults are less harsh in their judgment.

“Our research shows that children may be more gullible than adults, but the seeds of doubt are also present from an early age and develop dramatically in the elementary school years,” Candice Mills, a graduate student in psychology at the university, said in a statement.

For the study, published in the journal Psychological Science, Mills and psychology professor Frank Keil conducted two experiments with children in kindergarten and the second, fourth and sixth grades.

In the first, children in the three lower grades listened to short stories about characters trying to win a prize in a contest, such as a race. In a scenario in which a character, for instance, claimed to have won a close race, kindergartners typically believed that character was telling the truth. Older children, on the other hand, recognized the “self-interest” in such a claim and tended to be skeptical.

In the second part of the study, the children heard similar stories with an added twist; they were told when a character made a false statement. The children were then asked if they thought the characters were lying, made a mistake, or unintentionally made a false statement because of a bias.

In scenarios in which the misstatement was in the character’s self-interest, children in kindergarten, second and fourth grades usually said the character was lying. In contrast, sixth graders - who were about 11 years old - allowed for the possibility that bias, rather than intentional deceit, had swayed the character’s remarks.

Bias, Mills and Keil note, may be too difficult a concept for young children to grasp. Coupled with the healthy dose of skepticism that is beginning to develop early on, this may make young children among the harshest of judges.

“In a sense,” the study authors write, “young children seem to be even more cynical than adults ... assuming that people must be intentionally misleading others even when they may not be.”

SOURCE: Psychological Science, May 2005.