This research was supported by CIFA contract FA-4814-04-0011.
Stress and Deception in Speech: Evaluating Layered Voice Analysis*
Article first published online: 30 MAR 2009
© 2009 American Academy of Forensic Sciences
Journal of Forensic Sciences
Volume 54, Issue 3, pages 642–650, May 2009
How to Cite
Harnsberger, J. D., Hollien, H., Martin, C. A. and Hollien, K. A. (2009), Stress and Deception in Speech: Evaluating Layered Voice Analysis. Journal of Forensic Sciences, 54: 642–650. doi: 10.1111/j.1556-4029.2009.01026.x
- Issue published online: 21 APR 2009
- Article first published online: 30 MAR 2009
- Received 29 April 2007; and in revised form 21 July 2008; accepted 2 Aug. 2008.
- forensic science;
- psychological stress;
- voice stress;
- layered voice analysis
Abstract: This study was designed to evaluate commonly used voice stress analyzers—in this case the layered voice analysis (LVA) system. The research protocol involved the use of a speech database containing materials recorded while highly controlled deception and stress levels were systematically varied. Subjects were 24 each males/females (age range 18–63 years) drawn from a diverse population. All held strong views about some issue; they were required to make intense contradictory statements while believing that they would be heard/seen by peers. The LVA system was then evaluated by means of a double blind study using two types of examiners: a pair of scientists trained and certified by the manufacturer in the proper use of the system and two highly experienced LVA instructors provided by this same firm. The results showed that the “true positive” (or hit) rates for all examiners averaged near chance (42–56%) for all conditions, types of materials (e.g., stress vs. unstressed, truth vs. deception), and examiners (scientists vs. manufacturers). Most importantly, the false positive rate was very high, ranging from 40% to 65%. Sensitivity statistics confirmed that the LVA system operated at about chance levels in the detection of truth, deception, and the presence of high and low vocal stress states.