Vocal characteristics of accuracy in eyewitness testimony

Abstract

In two studies, we examined if correct and incorrect testimony statements were produced with vocally distinct characteristics. Participants watched a staged crime film and were interviewed as eyewitnesses. Witness responses were recorded and then analysed along 16 vocal dimensions. Results from Study 1 showed six vocal characteristics of accuracy, which included dimensions of frequency, energy, spectral balance and temporality. Study 2 attempted to replicate Study 1, and also examined effects of emotion on the vocal characteristic-accuracy relationship. Although the results from Study 1 were not directly replicated in Study 2, a mega-analysis of the two datasets showed four distinct vocal characteristics of accuracy; correct responses were uttered with a higher pitch (F0 [M]), greater energy in the first formant region (F1 [amp]), higher speech rate (VoicedSegPerSec) and shorter pauses (UnvoicedSegM). Taken together, this study advances previous knowledge by showing that accuracy is not only indicated by what we say, but also by how we say it.