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Posted by Rescue_Ranger
- Nov 08, 2001, 10:29 PMGeorge Maschke, an Especially Senior User and all around nice guy, caught Rescue Ranger explaining only half the point.
Micro tremor is a bit of a misnomer, it's really a small but correlated higher frequency component.
I can both inject or supress various frequencies at will into an electronic circuit (the telephone), or acoustically into free air, adn do it in real time (or onto a tape machine if you like)
If you have a PC with a modem, you probably could do a similar feat if technically inclined, as the software is pretty easy to get for other applications.
I don't really want to say what I'm doing, but I believe there are at least 3 ways of spoofing this system, and at least 1 appears to be very solid. Maybe there is a business is selling a very small box that provides appropriate supression / enhancement, or in teaching others how to blow their system or providing a service (after all, if there is so much faith put into this system by the manufacturer and over 1000 law enforcement units, then....)
Maybe we don't want to include the manufacturer, but use one of their systems in a very public demonstration....
RR
Note that CVSA is based on the assumption that the absence of microtremors in the voice is indicative of stress, and that stress is in turn indicative of deception. I don't know how global suppression of microtremors would affect outcomes. Perhaps it would be effective if done selectively on "control" questions (which in CVSA "tests" are known truth quesions, like "Is today Wednesday?").
What technique do you have in mind for suppressing microtremors over the phone?
Micro tremor is a bit of a misnomer, it's really a small but correlated higher frequency component.
I can both inject or supress various frequencies at will into an electronic circuit (the telephone), or acoustically into free air, adn do it in real time (or onto a tape machine if you like)
If you have a PC with a modem, you probably could do a similar feat if technically inclined, as the software is pretty easy to get for other applications.
I don't really want to say what I'm doing, but I believe there are at least 3 ways of spoofing this system, and at least 1 appears to be very solid. Maybe there is a business is selling a very small box that provides appropriate supression / enhancement, or in teaching others how to blow their system or providing a service (after all, if there is so much faith put into this system by the manufacturer and over 1000 law enforcement units, then....)
Maybe we don't want to include the manufacturer, but use one of their systems in a very public demonstration....
RR
Note that CVSA is based on the assumption that the absence of microtremors in the voice is indicative of stress, and that stress is in turn indicative of deception. I don't know how global suppression of microtremors would affect outcomes. Perhaps it would be effective if done selectively on "control" questions (which in CVSA "tests" are known truth quesions, like "Is today Wednesday?").
What technique do you have in mind for suppressing microtremors over the phone?
Posted by beech trees
- Nov 07, 2001, 10:28 AMIt's funny all this CVSA fraud is popping up in droves recently. It must be the recent Blue Moon! Regardless Mr. Rescue_Ranger, reporter Margie Wylie recently wrote in part:
"Voice stress analysis is a fraud. It has zero validity," said David T. Lykken, a psychology professor emeritus at the University of Minnesota in Minneapolis and author of the book "A Tremor in the Blood: Uses and Abuses of the Lie Detector."
A 1996 Department of Defense Polygraph Institute study of the CVSA found that the device performs no better than chance in detecting deception. In other words, guessing or flipping a coin would be as accurate as the test. Based on this study, the Department of Defense, the Central Intelligence Agency and the Federal Bureau of Investigation do not use voice stress tests.
The entire story can be read here
"Voice stress analysis is a fraud. It has zero validity," said David T. Lykken, a psychology professor emeritus at the University of Minnesota in Minneapolis and author of the book "A Tremor in the Blood: Uses and Abuses of the Lie Detector."
A 1996 Department of Defense Polygraph Institute study of the CVSA found that the device performs no better than chance in detecting deception. In other words, guessing or flipping a coin would be as accurate as the test. Based on this study, the Department of Defense, the Central Intelligence Agency and the Federal Bureau of Investigation do not use voice stress tests.
The entire story can be read here
Posted by George W. Maschke
- Nov 07, 2001, 04:25 AMI'm not sure how one would go about setting up a double-blind test of CVSA without considerable expense, and you can expect no assistance from the "National Institute for Truth Verification."
Note that CVSA is based on the assumption that the absence of microtremors in the voice is indicative of stress, and that stress is in turn indicative of deception. I don't know how global suppression of microtremors would affect outcomes. Perhaps it would be effective if done selectively on "control" questions (which in CVSA "tests" are known truth quesions, like "Is today Wednesday?").
What technique do you have in mind for suppressing microtremors over the phone?
Note that CVSA is based on the assumption that the absence of microtremors in the voice is indicative of stress, and that stress is in turn indicative of deception. I don't know how global suppression of microtremors would affect outcomes. Perhaps it would be effective if done selectively on "control" questions (which in CVSA "tests" are known truth quesions, like "Is today Wednesday?").
What technique do you have in mind for suppressing microtremors over the phone?
Posted by Rescue_Ranger
- Nov 07, 2001, 04:01 AMI've read the CVSA website and other related information on the detection of micro tremors.
Is there a simple way set up a double blind test, based upon well known factual events, to prove / disprove their statistical claims?
I did some basic signal analysis testing, and now believe I can supress the "micro tremors" in simple yes / no questions.
Replies via thread please, email addr is not valid.
Is there a simple way set up a double blind test, based upon well known factual events, to prove / disprove their statistical claims?
I did some basic signal analysis testing, and now believe I can supress the "micro tremors" in simple yes / no questions.
Replies via thread please, email addr is not valid.