Experiments on children's lying

Psychologists do it differently:

Children’s statements after they have told an initial lie further reveal the role of intentionality. In the temptation resistance paradigm, after children denied transgressing, the experimenter asked follow-up questions. For example, when children peeked at a toy (e.g., Barney) and lied about peeking, the experimenter asked, “What do you think it is?” Children’s answers reveal a marked developmental change between 2 and 7 years of age: Most 2- to 3-year-olds blurt out “Barney!” without hesitation, thus revealing that they not only transgressed, but lied .... With increased age, children try to avoid making such blatantly inconsistent statements. Initially, their efforts may be a little clumsy and inconsistent (i.e., semantic leakage): For example, a 5-year-old girl said, “I didn’t peek at it. I touched it and it felt purple. So, I think it is Barney.”

The paradigm involves more deception than experimental economists would like. But the results are much more adorable!