Most elementary school age children are harsher judges of others than adults and older children

By the time children are in second grade, they know to take what people say with a grain of salt, particularly when the statement supports the speaker's self-interest, according to a published study by Yale researchers.

"As adults, we recognize that a person's self-interests, such as their desire to win recognition or fit in with their peers, can influence what they say and believe about the world," said the lead author, Candice Mills, a graduate student in the Department of Psychology. "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."

The first part of the two-part study included 20 children each in kindergarten, second grade and fourth grade. The children were told very short stories in which characters made statements about the outcomes of contests that were in or against their self-interest. Children of all ages believed true statements more than clear lies. However, when characters made statements involving their self-interest about very close contests, children evaluated the statements in very different ways. Children in kindergarten were more likely to believe statements aligned with self-interest than statements going against self-interest, but by second grade they were much more savvy and they recognized that self-interest statements might not be accurate.

In the second part of the study the children were asked how self-interest might lead someone to make an incorrect statement. Children were provided with three choices: intentional deception, unintentional bias, or pure mistake. They rarely endorsed bias as the best possible explanation for being incorrect. The youngest children were more likely to think the characters were lying.

"It is not until sixth grade that children begin to endorse lies and biases as equally plausible explanations for self-interested incorrect statements," Mills said. "Adults are clearly sensitive to all three sources of inaccuracy. How children begin to understand what it means to be biased is an open question."

Frank Keil, professor of psychology and linguistics and senior author of the study, added that, "By distinguishing cases of outright intentional lies from cases where we unintentionally distort the truth in self serving ways, it was possible to show that most elementary school age children are in fact harsher judges of others than adults and older children. It seems that, early on, it is much easier to see falsehoods as caused by deliberate malice than as caused unwittingly by desires."