Identifying unfamiliar voices: examining the system variables of sample duration and parade size

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Pautz, N. ORCID: 0000-0002-5366-5925, Mcdougall, K., Mueller-Johnson, K., Nolan, F., Paver, A. and Smith, H. ORCID: 0000-0003-2712-5527, 2023. Identifying unfamiliar voices: examining the system variables of sample duration and parade size. Quarterly Journal of Experimental Psychology. ISSN 1747-0218

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Official URL: https://doi.org/10.1177/17470218231155738

Abstract

Voice identification parades can be unreliable due to the error-prone nature of earwitness responses. UK government guidelines recommend that voice parades should have nine voices, each played for 60 seconds. This makes parades resource-consuming to construct. In the present paper we conducted two experiments to see if voice parade procedures could be simplified. In Experiment 1 (N=271, 135F), we investigated if reducing the duration of the voice samples on a nine-voice parade would negatively affect identification performance using both conventional logistic and signal detection approaches. In Experiment 2 (N=270, 136F), we first explored if the same sample duration conditions used in Experiment 1 would lead to different outcomes if we reduced the parade size to include only six voices. Following this, we pooled the data from both experiments to investigate the influence of target-position effects. The results show that 15s sample durations result in statistically equivalent voice identification performance to the longer 60s sample durations, but that the 30s sample duration suffers in terms of overall signal sensitivity. This pattern of results was replicated using both a nine- and a six-voice parade. Performance on target-absent parades were at chance-levels in both parade sizes and response criteria were mostly liberal. Additionally, unwanted position effects were present. The results provide initial evidence that the sample duration used in a voice parade may be reduced, but we argue that the guidelines recommending a parade with nine-voices should be maintained to provide additional protection for a potentially innocent suspect given the low target-absent accuracy.

Item Type:

Journal article

Publication Title:

Quarterly Journal of Experimental Psychology

Creators:

Pautz, N., Mcdougall, K., Mueller-Johnson, K., Nolan, F., Paver, A. and Smith, H.

Publisher:

SAGE Publications

Date:

31 January 2023

ISSN:

1747-0218