Distinguishing between science and pseudoscience in forensic acoustics

Abstract

In this presentation I argue that one should not attempt to directly assess whether a forensic analysis technique is scientifically acceptable. Rather one should first specify what one considers to be appropriate principles governing acceptable practice, then consider any particular approach in light of those principles. I focus on one principle: The validity and reliability of an approach should be empirically tested under conditions reflecting those of the case under investigation using test data drawn from the relevant population. Versions of this principle have been key elements in several reports on forensic science, including forensic voice comparison, published over the last four-and-a-half decades. I consider the aural-spectrographic approach to forensic voice comparison (also known as "voiceprint" or "voicegram" examination) in light of this principle, and also the currently widely practiced auditory-acoustic-phonetic approach (these two approaches do not appear to be mutually exclusive). Finally, I challenge the audience members to consider what each of them thinks constitutes the relevant principles regarding acceptable practice, and then consider their own approach to forensic-acoustic analysis in light of those principles.