A method for calculating the strength of evidence associated with an earwitness’s claimed recognition of a familiar speaker

Claudia Rosas, Jorge Sommerhoff, Geoffrey Stewart Morrison*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

The present paper proposes and demonstrates a method for assessing strength of evidence when an earwitness claims to recognize the voice of a speaker who is familiar to them. The method calculates a Bayes factor that answers the question: What is the probability that the earwitness would claim to recognize the offender as the suspect if the offender was the suspect versus what is the probability that the earwitness would claim to recognize the offender as the suspect if the offender was not the suspect but some other speaker from the relevant population? By “claim” we mean a claim made by a cooperative earwitness not a claim made by an earwitness who is intentionally deceptive. Relevant data are derived from naïve listeners' responses to recordings of familiar speakers presented in a speaker lineup. The method is demonstrated under recording conditions that broadly reflect those of a real case.
Original languageEnglish
Pages (from-to)585-596
Number of pages12
JournalScience and Justice
Volume59
Issue number6
Early online date9 Jul 2019
DOIs
Publication statusPublished - 1 Nov 2019

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Bibliographical note

Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Keywords

  • Bayes factor
  • Earwitness
  • Familiar speaker recognition
  • Likelihood ratio
  • Strength of evidence

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