Pitch changes during attempted deception

Two studies on speech samples from 32 male college students are reported. In the first, it was shown that the average voice fundamental frequency of the subjects was higher when lying than when telling the truth. In the second, judges rated the truthfulness of 64 true and false utterances either from an audiotape that had been electronically filtered to render the semantic content unintelligible or from an unfiltered tape. The truthfulness ratings of the judges who heard the content-filtered tape were negatively correlated with fundamental frequency, whereas for the unfiltered condition, truthfulness ratings were uncorrelated with pitch. Although raings made under the two conditions did not differ in overalll accuracy, accuracy differences were found that depended on how an utterance had been elicited originally.