A Close Look at Lie Detector Tests

Lying can become a habit that’s hard to break. Unfortunately, lying has several negative effects to one’s life, relationships and even employment. In a criminal case, for instance, lying can make or break the litigation proceedings, and could deny justice when it is due.

It’s for this reason that lie detectors were invented. It’s a very useful device that could help in an investigation or proceeding in which the truth needs to be established or discerned. Let’s take a look at lie detector tests, and learn how they came into being and how they work.

History of the Lie Detector

The lie detector test was invented only a century ago. It was in 1902 when the first primitive lie detector was unveiled to the public.

The first detector was invented by a British surgeon, Dr. James Mackenzie. It worked the same way as contemporary lie detectors do. By attaching a rubber diaphragm to both a neck artery and another one in the wrist, the device monitored and measured heart activity by printing the heartbeats in a paper.

However, Mackenzie’s lie detector was considered as inaccurate – this is hardly surprising, given how experimental and new the technology was. Nevertheless, the device was effective at measuring and recording changes in heartbeat in response to stimuli.

Other intellectuals slowly improved on the design and functionality of the polygraph, as the lie detector is alternatively known. Barely 19 years after Mackenzie’s design was first showed, an improved machine was developed by American John Larson in 1921.

Larson’s design underwent several more improvements in 1925, and in 1938. Both of these versions were developed and improved by Leonarde Keeler.

The technology continued to improve and become more efficient and accurate over the decades, and a quantum leap was achieved when lie detectors finally assimilated themselves into the digital age. In 1992, a computerized version entered the market boasting of all the advancements that computers could bring.

https://www.liedetectortest.ukWhat Do They Do?

Polygraphs measure a host of physiological data. Mackenzie’s device merely recorded only pulse rates, but the later devices are able to do more than that, thanks to the efforts of the scientists who developed the technology.

Modern lie detectors can now detect other physical manifestations that are considered as symptoms of stress, under the theory that people experience stress when telling something that is untrue. These symptoms include changes in the rate of sweating — galvanic skin resistance — and increased heart rates.

Polygraphs themselves don’t really detect lies, because that is the job of the analysts who ask what they call as “control questions.” Analysts merely monitor the changes, note their timing and make their conclusions later on.

They may have become more efficient at what they do, but, at their core, lie detector tests remain faithful to the original design that Dr. Mackenzie developed.

Take a look at the lie detectors at if you want to learn more about how these machines work, and what different models are up on the market right now.