John A. Larson is widely credited for inventing the modern polygraph machine. While many inventors preceded and succeeded him, Larson’s efforts laid the groundwork for the lie detector equipment as we know it today.
Larson is perhaps best known for his breadboard polygraph. Unlike previous lie detector equipment that measured physiological functions sporadically, the breadboard could track several variables simultaneously.
Larson’s breadboard would later undergo significant iterations. That includes major advancements from the early-1990s, marked by the eventual digitalization of lie detector machines.
Yet, the breadboard remains arguably the most critical invention in modern forensic polygraphy. Here’s a look at how Larson’s new-fangled device redefined deception detection.
Before the Breadboard
The breadboard emerged in 1921. However, the polygraph history goes way back.
In 1875, Italian criminologist Cesare Lombroso developed the first version of a lie detector test machine called the hydrosphygmograph.
The same year, Italian scholar Angelo Mosso performed experiments using plethysmography to assess how the fear response impacted heart rate and respiration. Mosso later invented the sphygmomanometer.
In 1879, French therapist Marie Vigouroux built upon Mosso’s theory by pioneering studies on the skin’s electrical conductivity during lying.
German scientist Georg Sticker later confirmed that electrodermal activity, indeed, changed in response to deception. He suggested using the psychogalvanometer to sniff out liars.
In 1909, Swiss neurologist Otto Veraguth used the first galvanometer. Veraguth coined the phrase psychogalvanic reflex (which later changed to electrodermal response) to denote the skin’s electrical changes in response to lying.
Between 1915 and 1917, William Marston developed a lie detector machine that focused on systolic blood pressure changes.
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Enters the Breadboard
The breadboard polygraph was a pioneering lie detector tool by John A. Larson. Its invention was reportedly a joint effort, with Larson claiming most credit.
Developed in 1921, the breadboard became one of the first polygraphs to simultaneously and continuously capture physiological recordings. Larson created the breadboard to improve existing lie detector tests. For perspective, the equipment’s predecessors recorded blood pressure and respiratory measurements discontinuously.
A cardiosphygmograph would only capture one or a few readings relative to the number of questions asked. This meant certain responses by the examinee went unrecorded, severely impacting the quality of the data collected.
With Larson’s invention, a cardiosphygmograph now responded each time an examinee answered a polygraph question. This applied to the other polygraph attachments – pneumographs and (later) electrodermal sensors – which all functioned simultaneously.
Deal Behind the Name
The name “breadboard” was a nod to the tool’s base, which featured a wooden breadboard.
The Breadboard’s Functionality
Like most polygraph devices around the same period, the breadboard was relatively easy to use. The tool initially focused on analyzing blood pressure and respiratory changes in response to polygraph questioning.
In 1938, Larson’s protégé – Leonarde Keeler – added the psychogalvanometer to Larson’s breadboard. This became the first significant improvement to the lie detector tool.
With all three components fully integrated, the breadboard now functioned similarly to modern polygraph machines.
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Why Is the Breadboard Considered Revolutionary?
1. Introduced Simultaneous Testing
Larson’s breadboard was the first polygraph machine to perform continuous lie detector tests.
Unlike its predecessors, this equipment tracked multiple physiological variables simultaneously. It was a significant step up from manual, rudimentary lie detector tools that worked more sporadically.
By recording an examinee’s physiological data continuously rather than a few times, the breadboard provided examiners with higher-quality data to accurately infer deception.
No longer would polygraphers rely on one erratic heart rate or breathing pace to prepare their reports. Instead, they’d now need to analyze data recorded from examinees’ responses to each in-test question.
The fact that there were more variables to analyze (heart rate, respiration, and, later, perspiration) further enhanced the breadboard’s reliability.
2. Pioneered Standardization
The breadboard garnered instant attention for its efficiency compared to its predecessors.
For industry leaders, the equipment signaled a welcome departure from subjective interrogation methods to a more standardized and scientifically approved technique.
Note that standardization (or the lack thereof) is a key ethical issue surrounding lie detector tests.
Besides publishing approved polygraph testing methodologies, the American Polygraph Association (APA) also emphasizes using reliable equipment.
As the first machine that captured multiple physiological data simultaneously, the breadboard quickly phased out other existing inventions to become the standard for gauging polygraph’s reliability.
3. Helped Develop the Frye Standard
Shortly after inventing the breadboard, Larson deployed it during a criminal investigation at the Berkeley Police Department. And the machine didn’t disappoint.
One of the most significant legal precedents linked to the breadboard was set in 1923, when Larson’s breadboard was deployed in the Frye v. United States case.
Polygraph findings from the breadboard test were disallowed. However, the case led to the establishment of the popular Frye Standard on evidence admissibility.
According to the Frye Standard, a theory or technique must attain a general acceptance within its scientific community to be legally permissible. The standard continues to determine the admissibility of polygraph reports in US courts.
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Wrap Up
John A. Larson’s breadboard stood out from previous polygraph iterations for its ability to continuously monitor several physiological variables. By recording multiple signals simultaneously, the breadboard provided a more reliable way to discern deception than its predecessors.
The breadboard also streamlined the polygraph process by minimizing unnecessary breaks. Examiners would perform one continuous test and embark on report writing rather than undertake several exams, each targeting specific physiological functions.
Modern lie detector machines borrow heavily from the breadboard, making Larson’s invention one of the most critical devices in the development of the polygraph.
