Do Young Children Always Say Yes to Yes–No Questions? A Metadevelopmental Study of the Affirmation Bias


concerning this article should be addressed to Kang Lee, Department of Psychology, University of California at San Diego, La Jolla, California 92093-0109.


The present study investigated whether yes–no questions would lead to a yes bias in young children. Four experiments were conducted in which 2- to 5-year-olds were asked comprehensible and incomprehensible yes–no questions concerning familiar and unfamiliar objects. Consistent findings were obtained: (a) 2-year-olds displayed a consistent yes bias; (b) 4- and 5-year-olds exhibited no response bias toward comprehensible questions and a nay-saying bias toward incomprehensible questions; and (c) 3-year-olds' results were mixed, suggesting that the age of 3 years is a period of developmental transition in response tendency toward yes–no questions. The findings suggest that yes–no questions are suitable for older children, providing they are comprehensible, but may result in biased results when used with younger children and when incomprehensible.