Can you handle the truth?
Software examines voice patterns to search for deception
- By John Breeden II
- Aug 29, 2003
Thou shalt not lie. It's a simple rule, but everyone breaks it at some point, even if only with harmless white lies such as, 'Gee, your new haircut doesn't look bad.'
But it's the job of many government agents to distinguish between the little white lie and its more notorious counterpart. The government wants a way to do so quickly, too'at the nation's border crossings.
The time-honored polygraph test that relies on respiratory and perspiration monitors is too time-consuming, and some experts believe a polygraph can be beaten with special techniques, or that it doesn't work reliably enough to be trusted.
V LLC of Washington has been working on an alternative to the bulky polygraph gear. The PC-based Layered Voice Analysis system measures vocal parameters to analyze a subject's truthfulness.
V LLC loaned the GCN Lab the software for testing on a notebook PC, with the caveat that it must be stored in a secure room and protected by biometrics for security reasons. By the time you read this, the lab will have deleted the software from its lab equipment.
Layered Voice Analysis is not a lie detector. Some might say it's a truth detector, though that isn't exactly correct either. The software works by measuring the emotional content in voice patterns independent of language or culture, its maker said.
In our tests, the software could spot two types of deception. First, it could identify when a subject's belief differed from what was actually said. Second, it could tell when a subject was thinking too hard about the answer'a clue that the answer might have been rehearsed.
It takes a trained questioner, however, to ferret out the truth. In one interview, I asked a colleague who had gone with him on his vacation trip. He replied, 'My wife.' The software indicated a large amount of stress, so I asked whether his wife was the only person who went along, and the answer was yes.
The test system flashed me an SOS, indicating that my colleague was not trying to deceive but not telling the whole truth either.Further probing
I began to ask more questions. At first I wondered whether another woman might somehow be involved, except that I knew the guy and didn't believe that could be so.
After several more minutes of questioning, my colleague said his wife had not wanted to go because she didn't want to leave their daughter behind. The subject was also worried about that.
Further questions led to the disclosure that the daughter had been injured once while staying with her grandparents and my colleague blamed himself for going on the trip and leaving her behind.
Layered Voice Analysis was adept at detecting misleading or incomplete answers even when a subject was not fully aware of being deceptive. For example, I asked another colleague what he'd done over a weekend. He replied that he had gone to a friend's house. A highly stressed warning flashed when he said friend.
Questioning revealed that the person visited was more a coworker than a friend, and that my colleague had wanted to be somewhere else. He admitted he was embarrassed but the system was right. The visit had been more a work obligation than weekend fun.
Besides showing a high rate of accuracy in our tests, Layered Voice Analysis was not invasive. A small microphone could be placed inconspicuously in front of the person being questioned. An agent could record the conversation to run it through the system later, which would give the advantage of secrecy. It could also be set up to work by telephone.Interface problems
The biggest drawback was not the technology, which I believe is solid, but the user interface.
The program was difficult to use, and it stubbornly took control of Microsoft Windows functions and then set sound levels incorrectly. It forced the microphone input level to mute, which made recording inaudible. And it didn't alert me when it did so.
The software even destroyed the mixer program on one of the lab's notebook PCs.
If the interface were friendlier, this application would make an excellent tool for law enforcement and security organizations. Intelligence agencies also might be able to use it to catch moles and spies within their organizations.