VIPRE News

Voice Stress Analysis (VSA), VSA Analyzers, and Associated Training

by Lawrence Rice, VSA Instructor, VIPRE Technology Group, LLC August 2023

Establishing the Truth

We know that when emotional stress is accompanied by guilt and a known consequence, e.g. punishment will cause the body to physically react. This stress is often overtly revealed in the form of observable reactions such as sweating, a shaky voice, dry mouth, increased body odor, runny nose, upset stomach, and hives, or coupled with other notable body movements; i.e. body language. These overt responses are commonly referred to as the "Fight or Flight Syndrome." The central nervous system which supports the autonomic branch makes these overt responses uncontrollable. The central nervous system, brain, and spinal cord integrate this sensory data via a pathway known as the vagus nerve. When the brain receives and interprets information from questions being asked, this information may or may not produce stress, depending on guilt and the consequence involved. Once stressful information is learned, the brain sends a message through the vagus nerve and subsequent recurrent laryngeal nerve resulting in a proportionate reaction in the vocal cords.31,32,33,34,35

The Voice Stress Analyzer

Using an industry-approved voice stress analyzer, regardless of the manufacturer allows for the capture and display of emotional stress generated by questioning.36 Once displayed, the evaluation of a voice stress pattern is primarily dependent upon an examiner’s interpretation (which is subjective and based on examiner training and experience).37,38,39 Properly interpreting voice stress patterns, like that of charts from a polygraph, is a skill that has to be learned and then mastered through experience.40 Not all voice stress analyzers are created equal; however, most use a standard computer algorithm to detect emotional stress in someone’s voice and then display it for evaluation. Aside from the algorithm used to capture the stress in the voice, differences between analyzers for the most part are limited to menu options and orientation on how the analyzer displays the collected voice patterns.41

Voice Stress Training

Statements from VSA manufacturers and professional VSA associations that claim they are the sole training provider for specific VSA analyzers are baseless. Despite these claims, there are no federal or state regulations defining from whom VSA examiners must receive training. It should be noted the lion-share of VSA instruction usually follows and adheres to standards and protocols set by the voice stress industry.42 A review of industry-approved, voice stress analyzers reflect these standards and protocols appear to be consistent between manufacturers and professional VSA associations.43,44 Any differences in training are usually found in the personalities of the instructors and their delivery of instruction. It remains the responsibility of the VSA examiner and their respective agency to ensure whatever training is received, meets industry standards. Since 1995, the International Association of Voice Stress Analysts (IAVSA) has been a cornerstone in establishing and refining these standards and protocols. The IAVSA provides training that meets and exceeds the voice stress industry standards and protocols, thus providing VSA examiners an affordable option for their training and certification.