Your six-year-old knows when you're lying, study shows

If children catch adults lying, or not telling the whole story, they will not trust what they say, an MIT study finds

PUBLISHED : Sunday, 15 June, 2014, 3:50am
UPDATED : Tuesday, 17 June, 2014, 12:39pm

Children are remarkable judges of the people around them, with studies having shown them to be able to tell when someone is lying. Now researchers have found they pick up on more subtle aspects of misinformation such as when someone is telling only part of the truth.

In a paper published by the journal Cognition, scientists at the Massachusetts Institute of Technology have found that children can tell when someone is not giving them the whole story, and they learn not to trust the information that such a person gives them.

Understanding "sins of omission" might sound a sophisticated skill better suited to adults, but it is especially important for children. After all, most of the information they are absorbing from their surroundings is coming from adults telling them how the world works.

"Much of what we know about the world comes from what others tell us. However, informants can be ignorant, mistaken, withholding, or even deceptive," the study authors wrote. "Rather than indiscriminately accepting all socially communicated information, learners need to know whom to trust."

The MIT researchers wanted to know whether young children were capable of this sort of evaluation. So they recruited 42 children between the ages of six and seven who were visiting a Los Angeles children's museum, separated them into two groups and gave each group a different pyramid-shaped toy to play with.

One toy had only a twisting purple knob that controlled a wind-up mechanism; the other looked similar, purple knob and all, but also sported a button that triggered LED lights, a second button that caused a spinning globe to whirl and a third one that made music play.

After each group was allowed to play with its own toys, a "teacher" puppet demonstrated only one function to another puppet: the purple twist knob. For the single-use toy, this didn't matter. For the multifunctional toy, however, this meant there were three other uses that the teacher was leaving out.

Then the researchers asked each group to rate the teacher on a scale of 1 to 20. Those who had a multifunctional toy gave the teacher a much lower grade than those whose toy had only one function. Apparently, the children had noticed that the teacher had not given the whole picture.

"Children understand that a teacher who provides accurate but incomplete information about a toy is less helpful than a teacher who provides accurate and complete information," the study authors wrote.

The scientists then ran a second experiment where they took 75 children, aged six, and did a slightly different experiment. Some were given the single-function toy to play with and later shown only about the purple twist knob. Others other were given the multifunctional toy and, as before, also shown only the purple twist knob. But the researchers also took a third group, gave them the multifunctional toy and were shown all four activities.

After that round was over, the researchers gave all children a new, totally different toy. It involved pulling a yellow tube out of a purple tube to make a squeaky sound. After the teacher showed the children how to do it, they were given three minutes to play with it.

The children who were taught everything about their toy, whether it had one or four activities, took the teacher's word for it and played with the purple-yellow squeaking thing. But those who knew the teacher had shown them only one out of four functions in the first toy took the time to explore the new toy in different ways, as though they knew they should take the teacher's information with a grain of salt.

"Thus by six years of age, children keep track of others' informativeness; when an informant's credibility is in doubt, children engage in compensatory exploration," the study authors wrote.

There is a lesson for adults. Watch what you say to children, because they are constantly evaluating you.

"When we teach children about the world," the authors write, "we also teach them something about ourselves."