research on adults and older adolescents has indicated that verbal and nonverbal coimnunication cues are utilized by listeners to assess speaker truthfulness and sincerity. some evidence suggests that truthfulness is inferred from the consistency between these two types of cues. the present study was designed to assess whether, and if so, at what age children use a consistency principle to determine truth and lying. twenty subjects (10 boys and 10 girls) from each of kindergarten, second, and fourth grade were shown videotapes of male and female stimulus persons providing concomitant verbal and nonverbal cues of matched valence (consistent) or of mismatched valence (inconsistent). after each verbal-nonverbal communication subjects were asked to judge whether the stimulus person was telling the truth or lying. results indicated that a consistency pattern was evident by fourth grade (age 9). additionally, sex differences were found indicating that the consistency pattern was more evident in females than in males.