Kingston is the most easterly city on the north shore of Lake Ontario at the junction of the St. Lawrence and the Cataraqui Rivers. It is often referred to as “the Limestone City.” It is also the home of Limestone Technologies, Canada’s only manufacturer of polygraph instruments and the Backster School of Lie detection. One of the first things new examiners are taught is how the polygraph works.
The involuntary nervous system runs in the background, most of the time we are not even aware of its activity. The best example of this is your heart. You do not have to think every time you want it to beat. It continually beats without any thought or control on your part. Some other examples of the involuntary nervous system would include the following: We have all been in the position that we have forgotten something in the car. It is a cold winter day, but you do not want to get all bundled up, so you slide your boots on and run out to the car. On a cold day you don’t have to be outside for very long before you start to shiver this happens without any thought or control on your part. Likewise, on a hot summer day you don’t have to exert yourself too much and you will start to sweat. Again, you do not have to think about it, it just happens. You have no control over it. In other words, you cannot start shivering or sweating just because you want to, and once you start you cannot just stop it either.
So how does this relate to lying? From the time that we are very young we are taught the difference between right and wrong. We are taught that it is wrong to lie. When we are caught lying there is always a consequence. We may get a spanking, made to go to our room, suffer disappointment from a parent and so on. What happens is that in a physiological sense it becomes much easier to tell the truth than it is to lie. When we tell a lie those physiological changes kick in. We cannot control or stop them. They are picked up by the polygraph and transferred to the computer. It is from these involuntary physiological changes that the examiner can tell if the person is being truthful or not.
The polygraph works through the central nervous system. The central nervous system has two divisions, voluntary nerves, and involuntary nerves.
When we do a polygraph, we are not too interested in the voluntary nervous system. You have complete control over it. For example, if you are asked to hammer a nail, you can hit that nail as hard as you want to or you may choose to just tap it. You and strike it in rapid succession, or you can take your time. If someone tells you to hit the nail you can hit it any way you choose, or you can refuse to hit it at all. It is because of this control that we have little interest in the voluntary nerves.
