Young Children's Competency to Take the Oath

Despite liberalization of the rules of evidence, children must still understand the difference between truth and falsehood, appreciate the obligation to tell the truth, and take some form of the oath before they are allowed to testify. The legal requirements raise three questions: (a) How should children's understanding be assessed? (b) What form of the oath should be used? and (c) Does understanding and/or oath-taking correlate with honesty? I review the research on these issues and present data from a series of studies involving maltreated and non-maltreated children. The research demonstrates that conventional methods of assessing children's understanding are prone to serious error and that young children may have difficulty understanding even simplified versions of the oath. I recommend more sensitive measures for qualifying children and a child-friendly version of the oath. I also review research testing the relation among oath-taking competence, oath-taking, and honesty, and present data from two studies demonstrating that the oath can affect children's honesty.