NCJ Number
187171
Journal
Journal of Forensic Sciences Volume: 46 Issue: 1 Dated: January 2001 Pages: 63-67
Date Published
January 2001
Length
5 pages
Annotation
This project explores an approach to speaker identification that involves comparing samples acquired at different points in time.
Abstract
The noncontemporariness of speech is important to both of the two general approaches to speaker identification. Ear-witness identification is one of them; in this instance, the time at which the identification is made is noncontemporary. A substantial amount of research has been conducted on this relationship, and it is now well established that an auditor's memory for a voice decays sharply over time. It is the second approach to speaker identification that is of interest in the current study. In this case, samples of a speaker's utterances are obtained at different points in time; for example, a threat call will be recorded and then later (often very much later) a suspect's exemplar recording will be obtained. In this instance, it is the speech samples that are noncontemporary, and they are the materials that are subjected to some form of speaker identification. Prevailing opinion is that noncontemporary speech itself poses just as difficult a challenge to the identification process as does the listener's memory decay in ear-witness identification. Accordingly, a series of aural-perceptual speaker identification projects were conducted on noncontemporary speech. First, two were performed with latencies of 4 and 8 weeks, followed by 4 and 32 weeks, plus two more with the pairs separated by 6 and 20 years. Mean correct noncontemporary identification initially dropped to 75-80 percent at week 4, and this general level was sustained for up to 6 years. It was only after 20 years had elapsed that a significant drop (to 33 percent) was noted. Thus, a listener's competency in identifying noncontemporary speech samples will show only modest deterioration over substantial periods of time; this factor should have only a minimal negative effect on the speaker identification process. 2 tables, 2 figures, and 43 references