Since the time humans first began communicating with one another and told lies, we have been telling them. We also have tried to discern the lies from the fact and this requirement became increasingly important when societies developed legal systems. Police and other authorities who investigate crimes know that the capacity of humans to detect truth is limited, however we have the capability to develop technology that can detect signals that are beyond our capabilities. Polygraphs were the initial technology for truth verification that proved that we can use technology to identify deceit, but what does this technology mean against the current situation?
This is the History Behind The Polygraph
The polygraph is now referred to in the form of the “lie detector” however, that is an oxymoron. There isn’t a scientifically proven method of detecting the lies of a person, but there are methods to gauge the psychophysiological effects triggered by stress from being deceived. This is the reason why this concept has led to the development of the polygraph and later, more sophisticated technology for verifying truth, like the computer-generated Voice Stress Analyzer (CVSA(r)).
The year was 1878. Italian physiological scientist Angelo Mosso examined the physiological responses of individuals when asked questions using an instrument called a plethysmograph to gauge cardiovascular and respiratory reactions. Many other scientists rediscovered his work and made improvements to it.
An Canadian psychologist named John A. Larson created a variant of the polygraph when in the Berkeley (California) Police Department. He named the device “polygraph” which comes from the Greek “polygraphos,” which is a reference to “much writing.” The device could read blood pressure and graph it as well as respiration and pulse. Leonarde Keeler further contributed to the device in 1938 by adding sensors to measure the galvanic skin reactions.
The present polygraph model operates in a similar way to the ones that were invented around 100 years ago. They measure the body’s responses using sensors on the body, including a blood pressure cuff for measuring blood pressure and heart rate as well as pneumograph tubes for measuring respiration, and galvanometers tacked to the fingertips to gauge sweat.
In the late 1940’s Chicago attorney John E. Reid further developed the polygraph method. Reid developed The Reid Technique, an interview and interrogation method that is widely used by law enforcement agencies with and without polygraph test.
The modern polygraph is digital and, despite operating with the same principles that it does with sensors, just like the old analog one that it utilizes an algorithm to analyze the data and then display it in a computer software.
Polygraph Vulnerabilities
Chicago attorney William Scott Stewart wrote an article that was published within the issue of November 1941 in Esquire Magazine titled “How to defeat the Lies Detector.” It is most likely the first publication focused on countermeasures to the polygraph. Stewart stated that you could alter the results of the polygraph by increasing your feelings when you are asked innocent questions. These “control inquiries” are typically asked at the time of the Control Question Test (CQT) and are designed to provide comparisons to the questions that are relevant. In terms of physical countermeasures Stewart recommended biting your tongue or inside the mouth, or making movements that aren’t visible by the person who is performing the action like the toe moving or flexing the leg muscles.
The polygraph remains vulnerable to psychological as well as physical countermeasures, and has a high error rate that is based on inconsistent, false positives or false negatives.
Manipulation in Control Questions:
Subjects are able to manage their breathing
Sphincter muscles contract
The tongue is biting or inside of the mouth
The thought of horrible things
The former examiner of the polygraph and Oklahoma City Detective Sergeant Doug Williams was sentenced to two-years in prison in the year 2015 for actions related to his efforts to teach people on how to defeat the polygraph. After several years of using this technology, he began to doubt its results and instructed thousands of people how to use techniques to defeat the polygraph. Williams rates its accuracy as 50% at the most. In reality, U.S. government agencies have trained individuals who participate in undercover investigations to defeat the polygraph. This confirms Williams assertion that methods are taught in order to beat the polygraph.
Manipulation During Relevant Questions
Practicing relaxation techniques
Mental calculations
The thought of calm subjects
The positive impact of the Polygraph
Despite its flaws polygraph set a new benchmark in the use of truth-verification technology in the police interview process . It also opened the door to new innovations in the future. The polygraph community is an influential lobby and many loyal customers. Many examiners educated to utilize this technology are not willing to re-invent their expertise or invest in technology that is more modern However, around thirty of the most prestigious polygraph studies suggest that this truth-verification tool isn’t as reliable as people would think it is. The results of studies vary in assessing the precision of the polygraph with estimates that range between 70 and 90 percent accuracy. In addition only 29 percent from 194 “scientific studies” claimed to be proof by advocates of the polygraph meet the minimal standards of scientific quality, as per The 2003 National Research Council report by the Committee to Review the Scientific Evidence regarding the Polygraph.
Evidence from polygraph forensics is admissible in court. the states that allow it are 19 and in accordance with the specific requirements of every state. The technology is also employed for pre-employment screening in both the private and public sector. One of the main advantages for the polygraph test is it could be used to prompt confessions following examinations in cases where the subjects feel that deceit was discovered. However, in the modern Internet Age, individuals who are subjected to polygraph tests are able to access information on the polygraph that was previously unavailable and, in some instances not available to the public.
