Today, most of us are familiar with the polygraph machine, or, as it is commonly called, the “lie detector”. While some people have encountered the device in real life, most of us have learned about it through pop culture. We’ve seen people strapped to them in every procedural show. If a murder suspect fails a polygraph test or refuses to take one, it’s often considered “proof”—if not admissible evidence—that they are the killer. And of course, they’re a stable of daytime television shows that focus on cheating partners and paternity tests.
Because of this, I was surprised to find a polygraph machine in one of the boxes in our backlog. This machine was given to the museum by George Cheever Shattuck (1879-1972) in 1929. Shattuck was a prominent Boston physician, best known for his work in the field of tropical medicine. Why would a physician have a polygraph machine?
Although the polygraph is known colloquially as a lie detector, that isn’t exactly what it does. The machine detects changes in bodily function that indicate stress, which could be a result of lying. This includes functions like breathing, heart rate, and perspiration—all of which are also important baseline health measurements. With this in mind, it makes sense that the original polygraph machine had nothing to do with lies and criminal investigation: it was actually a medical device.
At the turn of the century, Dr. James Mackenzie (1853-1925) developed the first ink-writing polygraph to track a patient’s irregular heartbeat. While simpler than the polygraph that most of us are familiar with today, this device works in much the same way. It features two rubber tambours, one of which was attached to a vein in the neck and the other to the wrist. These tambours would move with the patient’s pulse, and the waves of this movement would be sent down rubber tubing to two recording arms with needles. Then, the needles would record the pulse as a continuous ink-line on paper. The doctor could simply look at the paper to determine the pattern of a patient’s heartbeat.
At the time that he introduced the machine, there wasn’t an effective way for physicians to track the pattern of a patient’s heartbeat. It was replaced by the electrocardiogram machine (or EKG) shortly after, making the Mackenzie polygraph a short but important segment of the history of cardiology. Mackenzie probably never imagined what his machine would eventually become known for, but nevertheless, his legacy continues to this day.
This news post was originally published on the Center for the History of Medicine’s Wordpress site.