How Does the Computer Voice Stress Analysis Test Work?

The Computer Voice Stress Analysis Test is a way to measure stress levels in the voice in order to find out if someone is telling the truth or is lying. It is sometimes used in criminal investigations in the USA.

How Does It Work?

The way is works is actually fairly simple. The software detects involuntary changes in the movement of the vocal muscles, and as these cannot be controlled by the subject, it provides an indication that the subject may be lying or nervous). These patterns are compared with the subject’s voice when speaking normally.

As with the polygraph test, the Computer Voice Stress Analysis Test is not completely fool-proof but many experts agree that it is more reliable.

Advantages of the Computer Voice Stress Analysis Test

One great advantage of the computer voice stress analysis test is that it is not as stressful for the subject as the polygraph. It only requires that a microphone is clipped to the clothes, and therefore the person under test feels freer to speak normally. 

Once the Computer Voice Stress Analysis Test is ongoing, it can help to encourage the subject to confess. According to criminal investigators, when a subject sees the results, he or she is more likely to give up lying and tell the truth. After all it seems little point in continuing to lie if computer technology shows clearly that the subject is not telling the truth.  

An added advantage of the Computer Voice Stress Analysis Test that it can be used in covert investigations where the subject does not realise he or she is even being recorded. This is working well in many types of undercover police work including counterterrorism.

Disadvantages of the Computer Voice Stress Analysis Test

There have been some issues with the test, and not everyone is onboard with its use. Critics have argued that some subjects are put under stress by the situation and will be marked down as lying when they might be telling the truth. In a high profile murder case in Wisconsin in 2014, a man falsely admitted to killing his mother after failing the test. When further DNA was provided, he was acquitted after serving 15 years in prison.

It is always important to bear in mind that with all technology, there is always a margin of error. The Computer Voice Stress Analysis Test is a great tool that is at the disposal of law enforcement agencies, and it can help secure convictions by indicating that someone is not telling the truth.

However, it is important that this test does not replace other forms of investigation or evidence gathering when looking to secure a conviction.