EvidenceProf Blog

Editor: Colin Miller
Univ. of South Carolina School of Law

Thursday, June 5, 2008

Follow My Voice: New York Missing Child Case Raises Questions About Admissibility Of Digital Voice Analyses

The Jaliek Rainwalker case in Guilderland, New York, provides a nice opportunity to discuss digital voice analyses.  Rainwalker has been missing since last November, and police consider his father, Stephen Kerr, a "person of interest" in the child's disappearance.  T.J. Ward from Georgia and Tom Winscher from Wisconsin donated their services in the case.  Specifically, Winscher listened to a 28-minute interview of Kerr and his wife, Jocelyn McDonald, in early December and used a digital voice analysis that he says can be applied to recordings and uses changes in the subject's voice to gauge truthfulness.  An article on the case, however, notes that "Like the results of a lie detector test, findings are not admissible in court."

My research reveals, however, that such a sweeping statement is unwarranted.  Let's start with the opinion of a New York trial court in 1982 in People v. Bein, 114 Misc.2d 1021 (N.Y. Sup. 1982), which provides a nice description of digital voice analyses.  According to the court in Bein,

     -"[v]oice analysis rests on the unlikeliness that any two individuals could have the same voice pattern, vocal cavities or articulators.  [This analysis is done with a spectograph.]  Briefly, a sound spectrograph is a device which converts sound waves into electrical signals. These signals are transduced into mechanical energy which operates a stylus. The stylus ‘burns' a visual pattern onto a paper. This pattern is known as a sound spectrogram.  This spectrogram is commonly called a ‘voiceprint’.  The visual pattern displayed on the spectrogram is an analogue of the frequency, intensity, and duration of the sound waves introduced into the spectrograph.  Spectrographic voice analysis consists of using these visual arrays to compare two exemplars of voices to see whether or not the same person spoke on each exemplar."

In Bein, the court found that the results of a spectograph voice analysis were reliable and admissible into evidence.  In 1992, the Court of Appeals of New York (the equivalent of most states' supreme courts), reviewed a trial court's decision to admit voice spectrographic evidence without a preliminary inquiry into its validity in People v. Jeter, 600 N.E.2d 214 (N.Y. 1992).  The Court reviewed New York precedent and found that "New York courts are split on the issue of admissibility." Id. at 216.  The Court of Appeals then neither approved or disapproved of either line of precedent, but it did find that the trial court erred in admitting the voice spectrographic evidence without a preliminary inquiry into its validity.  Thus, unless I am missing a subsequent Court of Appeals case or statute precluding the admissibility of digital voice analyses (or if the specific type of voice analysis used by Winscher is inadmissible), the article's sweeping statement was unwarranted.



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Take a look at Commonwealth v. Lykus, a recent (May) Massachusetts case:

"Report of the committee on evaluation of sound spectrograms. In March, 1976, the FBI asked the National Academy of Sciences to review the reliability of voice identification (voice spectrogram) techniques. In response, the NRC in July, 1976, appointed a committee to study the matter.
The NRC committee noted, among other things: "The practice of voice identification [indeed, its 'very foundation], rests on the assumption that intraspeaker variability is less than interspeaker variability. [That] assumption . . . is not adequately supported by scientific theory and data." NRC, On the Theory and Practice of Voice Identification 2, 10, 16 (1979).
The NRC committee found, among other things:
"Estimates of error rates now available pertain to only a few of the many combinations of conditions encountered in real-life situations. These estimates do not constitute a generally adequate basis for a judicial or legislative body to use in making judgments concerning the reliability and acceptability of aural-visual voice identification in forensic applications."
Id. at 60. Based on the NRC report, the FBI discontinued offering voice identification testimony in judicial proceedings. See 5 D.L. Faigman, M.J. Saks, J. Sanders, & E.K. Cheng, Modern Scientific Evidence: The Law and Science of Expert Testimony § 37:1, at 8 (2006)."

Posted by: Final Comment | Jun 5, 2008 10:25:56 PM

It's definitely a questionable technique, but at least for now, it's a technique which several courts still allow into evidence. It's definitely a subject that I think I will research more.

Posted by: Colin Miller | Jun 6, 2008 4:10:36 AM

Voiceprints are inadmissible in Michigan. People v. Tobey, 401 Mich. 141, 257 N.W.2d 537 (1977). One justice of the Michigan Supreme Court thinks the issue should be reconsidered. His dissent from an application for leave to appeal cites two cases that collect the eleven reported cases on each side of the question. People v. Hubbard, 480 Mich. 898, 742 N.W.2d 376 (2007).

Posted by: Greg Jones | Jun 6, 2008 11:38:03 AM

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