In “Speaker identification in courtroom contexts – Part I” individual listeners made speaker-identification judgements on pairs of recordings which reflected the conditions of the questioned-speaker and known-speaker recordings in a real case. The recording conditions were poor, and there was a mismatch between the questioned-speaker condition and the known-speaker condition. No contextual information that could potentially bias listeners’ responses was included in the experiment condition – it was decontextualized with respect to case circumstances and with respect to other evidence that could be presented in the context of a case. Listeners’ responses exhibited a bias in favour of the different-speaker hypothesis. It was hypothesized that the bias was due to the poor and mismatched recording conditions. The present research compares speaker-identification performance between: (1) listeners under the original Part I experiment condition, (2) listeners who were informed ahead of time that the recording conditions would make the recordings sound more different from one another than had they both been high-quality recordings, and (3) listeners who were presented with high-quality versions of the recordings. Under all experiment conditions, there was a substantial bias in favour of the different-speaker hypothesis. The bias in favour of the different-speaker hypothesis therefore appears not to be due to the poor and mismatched recording conditions.
This research was supported by Research England’s Expanding Excellence in England Fund as part of funding for the Aston Institute for Forensic Linguistics 2019–2024.
Copyright © 2023 The Author(s). Published by Elsevier B.V. This article is licensed under a Creative commons Attribution 4.0 International (CC BY 4.0)
- Forensic voice comparison
- Likelihood ratio
- Recording condition
- Speaker identification