On the use and misuse of the “Two Children” brainteaser

Cognitive scientists employ brainteasers, or “cognitive illusions” in service of cognitive research. In some cases, rewording or paraphrasing a question can change the correct answer, without the experimenter realizing. In recent published articles describing cognitive research, participants have pondered brainteasers, including what is here called the “Two Children” problem. Although many accounts of this problem in the academic literature navigate its nuances correctly, in the popular press it is usually presented such that the wording of the question does not actually compel the answer that is offered as correct. Unfortunately, cognitive scientists who have used this problem in research have adopted the more informal and ambiguous version that has become common in the popular press. Recent experiments have used the problem to demonstrate that people make common intuitive errors, but they unfortunately employ an ambiguous form of the question and the answer to the problem is not determinate, as they imply.