Children can tell when you omit information

Children may be able to tell when adults are telling them the truth, but not the whole truth, MIT scientists have found.
Researchers from the Massachusetts Institute of Technology found that children can tell when adults are omitting information.
Researchers found that not only can children make this distinction, but they can also compensate for incomplete information by exploring more on their own.
Determining whom to trust is an important skill to learn at an early age because so much of our knowledge about the world comes from other people, said Hyowon Gweon, an MIT postdoc and lead author of a paper describing the findings in the journal Cognition.

The study builds on a 2011 paper in which Gweon and others investigated how children behave when a teacher explains only one function of a toy that can do four different things.
They found that these children spent most of their time exploring only the function the teacher had demonstrated, assuming that was the only thing it could do.

However, children who received no instruction spent more time exploring all of the toy's features and ended up discovering more of them.
In the new study, Gweon wanted to investigate what the children thought of the teacher who did not fully explain what the toy could do.

In the first experiment, children aged 6 and 7 were given a toy to explore on their own until they discovered all of its functions.
One group received a toy that had four buttons, each of which activated a different feature - a windup mechanism, LED lights, a spinning globe, and music - while the other group was given a toy that looked nearly identical but had only one button, which controlled the windup mechanism.
Then the children watched as a "teacher" puppet demonstrated the toy to a "student" puppet. For both toys, the teacher's instruction was the same: He demonstrated only the windup mechanism.

After the demonstration, the children were asked to rate how helpful the teacher was, using a scale from 1 to 20.
Even though the teacher always demonstrated just the windup mechanism, children who knew the toy had three more undemonstrated functions gave much lower ratings than children who knew it was the toy's only function.
The second experiment began the same way, with the children exploring the toy, then seeing either a full or incomplete demonstration of its functions.
The teacher then brought out a second toy. Although this toy had four functions, the teacher demonstrated only one.
Children who had previously seen a demonstration they knew to be incomplete explored the toy much more thoroughly than children who had seen a complete demonstration, suggesting that they did not trust the teacher to be fully informative.