The California Department of Corrections and Rehabilitation had used the Computer Voice Stress Analyzer, or CVSA, for at least two decades to assess prisoners' credibility during internal investigations. This went on despite a litany of research indicating the technology was no better at detecting deception than a coin flip, and despite prisoners' rights advocates raising concerns about the tool on numerous occasions.
In May, following months of questions by the Chronicle, a corrections spokesperson said the department was "moving forward with regulations to end the use of CVSA across offices and institutions." The agency made its intentions official on Aug. 16 by publishing its proposed ban, which would take effect after a 45-day written comment period, followed by a public meeting Sept. 30.
"The department has determined there are more established and reliable techniques for detecting deception," the department, which did not immediately return a request for comment Monday, wrote in its proposal. "The current scientific consensus does not support the effectiveness or continued use of the CVSA."
The technology claims to work by analyzing inaudible tremors in the human voice that indicate whether the speaker is stressed or not — and by association whether they are lying. But decades of studies have debunked this mechanism, and speech sound experts have observed that no studies have confirmed the human voice produces the "microtremors" that the CVSA supposedly measures.
In one case examined by the Chronicle, Raymond Whitall, a prisoner at Salinas Valley State Prison in Soledad, took a CVSA exam after he filed a complaint accusing guards of beating him without justification. The prison threw out his complaint after his exam indicated "deception" in one of his responses to six questions, despite evidence of the beating documented by prison medical staff.
Richard Leo, a University of San Francisco professor of law and psychology and expert on false confessions, called the law enforcement use of CVSA "professional malpractice," and praised the prison system's move. "It's like saying a Ouija board or an astrological chart is an investigative tool," said Leo, who wrote about the CVSA in his book, "Police Interrogation and American Justice."
While California's prisons will no longer use the CVSA, the Chronicle's investigation identified 13 other law enforcement agencies around the state that were still using the technology to interview prospective officers during the hiring process. At least three of these agencies had also recently used the tool during criminal investigations.
At least one — the Berkeley Police Department — is now reviewing its use of the technology in response to the Chronicle's reporting.
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