|
Abstract:
|
The VSA systems are advertised as being less expensive, easier to use,
less invasive in use, and less constrained in their operation than
polygraph technology. In response to inquiries by law enforcement
officials about this technology, this testing and evaluation was
conducted by the Air Force Laboratory. The evaluation was conducted in
three phases. In the first phase, Dr. John H.L. Hansen Research
investigated the feasibility of detecting stress from speech. He
reports on the methods, analysis, and classification of voice stress
in an appendix of this report. The second and third phases of this
study investigated the reliability of two commercial VSA units (the
Vericator and the Diogenes Lantern) from a theoretical perspective and
an application (i.e., law enforcement) perspective.
The evaluation concludes that the two VSA units
do recognize stress through voice analysis; however, although
these systems state they detect deception, this was not proven.
This study does show, from a number of speech-under-stress studies,
that linear and nonlinear features are useful for stress
classification. Due to the lack of
deceptive stress data available, classification of deceptive stress
versus emotional stress or physical stress could not be tested.
It still needs to be proven whether or not these VSA systems
differentiate between the different types of stress. Suggestions are
offered for future research. 4 figures and 14 references.
|
