Voice Stress Analysis

Voice risk or voice stress analysis (VSA) technology is said to record psychophysiological stress responses that are present in the human voice when a person suffers psychological stress in response to a stimulus (e.g., a question), and the consequences of the person's answer may be dire. This is based on the belief that non-verbal content of the voice carries, among other things, information about the physiological and psychological state of the speaker. Manufacturers of VSA typically claim it can be employed to detect deception in a variety of settings such as police interviews, insurance claims, and social benefit claims.

In 1970, and prior to the publishing of Lippold's article in 1971, three military officers retired from the U.S. Army and formed a company they named Dektor Counterintelligence and Security (CIS). The three officers were Alan Bell, Bill Ford and Charles McQuiston. Bell's expertise was in counterintelligence, Ford's was in electronics, and McQuiston's was in polygraphy. Ford had invented an electronic device that utilized the theory of Lippold, Halliday and Redfearn in which he tape-recorded the human voice, slowed it down to one-third or one-fourth its normal rate, and fed it through several low pass filters which then fed the signal into an EKG strip chart recorder. The strip chart recorder then made chart tracings on heat-sensitive paper. They named their device the Psychological Stress Evaluator (PSE). According to Allan Bell Enterprises, "All lie-detection examinations or evaluations are predicated upon the fact that telling a significant lie will produce some degree of psychological stress. Psychological stress, in turn, causes a number of physiological changes."

The use of Voice Stress Analysis (VSA) technology to detect deception is highly controversial and use of these machines has been referred to as 'charlatanry' by academics. Discussions about its application revolve around whether this technology can indeed reliably detect stress, and if so, whether deception can be inferred from this stress. The latter is a logical inference problem referred to as the Othello error. It has even been argued that - even if stress could reliably be measured from the voice - this would be highly similar to measuring stress with for example the polygraph, and that all critiques voiced towards polygraph testing apply to VSA as well.

Several studies published in peer reviewed journals showed VSA to perform at chance level when it comes to detecting deception. Horvath, McCloughan, Weatherman, and Slowik (2013), for example, tested VSA on the recordings of interrogation of 74 suspects. Eighteen of these suspects later confessed, making the deception the most likely ground truth. With 48% accurate classification, VSA performed at chance level. Damhousse and colleagues interviewed over 300 arrestees about recent drug use. Their responses and the VSA output were compared to a subsequent urinalysis to determine if the VSA programs could detect deception. The results showed the programs were not able to detect deception at a rate any better than chance. Other peer reviewed studies showed similar results. In 2003, the National Research Council concluded “Overall, this research and the few controlled tests conducted over the past decade offer little or no scientific basis for the use of the computer voice stress analyser or similar voice measurement instruments”.

...
Wikipedia