Potential jurors' abilities to discriminate between accurate and inaccurate responses to interviewer questions were investigated. Young child witnesses were expected to be judged as less credible than older children and adult witnesses. Participant-jurors viewed videotaped interviews that paired an accurate respondent with an inaccurate respondent within same-aged pairs (Experiment 1) and different-aged pairs (Experiment 2). Juror discriminations were above chance in the same-aged pair conditions, but fell to chance when accurate young witnesses were paired against inaccurate older witnesses. Witness nonverbal behaviors were relevant to the prediction of correct discriminations in some, but not, all paired conditions. Results support and extend previous research showing that mock jurors are reluctant to believe the word of a young child in contrast to an older child or adult. Findings also highlight the impact that witness nonverbal behaviors can have on juror decisions. The findings are discussed in terms of their implications for juror deliberations.