Lie Detector or Polygraph is a test carried out as part of criminal investigation. It detects lies by monitoring the physiological changes in the body when subjected to stress.
Highlights:
"The worst lies are the lies we tell ourselves. We live in denial of what we do, even what we think"- Lie detectors monitor physiological responses like heartbeat and sweatiness but do not detect lies directly
- Advances include AI-driven analysis and compact voice stress gadgets for enhanced detection
- Despite advancements, skepticism about the accuracy and reliability of polygraphs persists
The ruthlessness of the crime has chilled the marrow of fair-minded people across the length and breadth of the country. The perpetrator(s), whose actions reflect a deeply disturbed mind, are a blot on humanity, and everything must be done to ensure that justice is served swiftly and decisively.
Most criminals, like the above mentioned, deny the crime they are charged with, and resort to consistent lying. A device that was launched with much aplomb, all over the world, to deal with criminals and tricksters is, the ‘Lie Detector’.
‘Did You Know?
Modern lie detectors now use AI and voice stress analysis to enhance accuracy. #medindia #lieDetector’
Modern lie detectors now use AI and voice stress analysis to enhance accuracy. #medindia #lieDetector’
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Where ‘lies’ truth?
Lying defies age and transcends barriers of class, creed and color. It is generously used as a defense weapon to save trouble, either with the law enforcers or with any figure of authority. Most of us lie and indulge in deception at some stage of our life, even if it is only in complimenting the looks of a person who is having a ‘bad hair day’! Many a marriage has been salvaged by timely lies, delivered with flair and ease. Generally, megaly of the nose does not occur on telling a lie, as in the fable ‘Pinocchio’. Therefore detecting lies, especially when dealing with hard-core criminals, becomes a ‘mission impossible’.If a criminal, who has maimed the well being of a society lies, then those words of deception need to be investigated with the gravity it deserves. The uneasy feeling that develops in one’s gut on hearing a lie, will not hold in a court of law. That is when the ‘lie detector’ steps in and attempts to delve into the dark recesses of the offender’s mind. ‘Lie Detectors’ are generally put to use by the police and by other investigating agencies when dealing with spies, hardened criminals and sometimes, first-time offenders.
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The Way the ‘Cookie’ Crumbles
Polygraphs, dubbed ‘lie-detector’ by the media, are a combination of medical devices designed to detect changes that occur in the body in response to stressful conditions. Contrary to popular belief, a polygraph does not detect lies. Instead, it monitors variations in certain physiological parameters, like heartbeat, blood pressure, respiratory rate and the sweatiness of the fingertip when a person is being interrogated. Some Polygraphs also record leg and arm movement.The subject sits on a chair and several air- filled tubes and wires are connected to the chest and abdominal region. A cuff is placed on the upper arm to detect blood pressure. Galvanometers or fingerplates are attached to the fingertips of the candidate. When subjected to questioning, variations in the physiological responses of the subject are translated into electrical signals that are registered on a graph. This is then compared to the standardized readings of normal responses. A signifant change is indicative of the examined person being deceptive. However, any conclusion that may be drawn from the readings of the polygraph rests with the interpretation of the examiner, who happens to be a Forensic Psycho physiologist (FP) (1✔ ✔Trusted Source
Beyond the Polygraph: Deception Detection and the Autonomic Nervous System
Go to source).
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Flurry of Querries
There are three basic approaches to questioning a subject during a Polygraph test. Three sets of questions are posed to a candidate and the responses to these questions are then noted.The Control Question Test (CQT) is conducted by asking the candidate questions related to the crime, and comparing the responses to those generated on asking questions related to a prior misdeed. The Directed Lie Test (DLT) prompts the candidate to deliberately lie, and compares the responses to those that are generated when the person is telling the truth. Several psychologists believe that both these tests lack scientific basis.
The Guilty Knowledge Test (GKT) on the other hand has scientific strength and is based on studying the physiological responses to multiple-choice questions, posed to the candidate, about the crime. One answer choice harbors information that only the criminal and the investigators are aware of (2✔ ✔Trusted Source
What is the control question other methods in polygraph test
Go to source).
Advances in ‘Unmasking’
The last decade has borne witness to the dramatic evolution of the polygraph. From the analog polygraphs of the past, which had small needles scripting on a single sheet of scrolling paper, the ‘lie detector’ has evolved into a sophisticated, state-of-the-art digital instrument. The scrolling paper has been substituted with algorithms and computerized monitors.Recent advancements have introduced ‘lie detecting’ gadgets with an LED display that are the size of one’s palm. These gadgets measure variations in a person’s voice that indicate if the person is deviating from the truth. Based on this concept, even popular communication platforms like Skype have installed lie-detecting facilities that claim to expose a deceiving conversation partner by analyzing stress levels in the voice (3✔ ✔Trusted Source
An Overview of Advancements in Lie Detection Technology in Speech
Go to source).
Furthermore, artificial intelligence (AI) has been integrated into modern polygraphy, where algorithms analyze facial microexpressions, vocal tone, and body language to enhance the accuracy of lie detection. Remote polygraphy, allowing tests to be conducted online, has also become more prevalent, especially during the COVID-19 pandemic, to facilitate the continuation of investigations without physical presence (4✔ ✔Trusted Source
Artificial Intelligence based Approach to Analyze the Lie Detection using Skin and Facial Expression
Go to source).
Voice of Dissent
Although the Polygraph endeavors to be a ‘promising forensic tool’, there are several detractors who challenge the credibility of the device as a ‘lie detector’ and attribute the technique to ‘voodoo science’. They contend that the polygraph, devoid of a scientific basis, is entirely based on a person’s ignorance and fear, and that a couple of deviant responses can falsely implicate a person, and ruin him for life.It is therefore imperative that more research is carried out to dissipate the air of ambiguity surrounding the device. This is in order not to coerce an innocent into ‘admitting’ a crime he did not commit, while ensuring that all the ‘tough cookies’, eventually, crumble.
''A truth that’s told with bad intent
Beats all the lies you can invent''
-William Blake
References:
- Beyond the Polygraph: Deception Detection and the Autonomic Nervous System - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6654171/)
- What is the control question other methods in polygraph test - (https://www.liedetectortest.org/post/control-question-other-methods-in-polygraph-test)
- An Overview of Advancements in Lie Detection Technology in Speech - (https://www.researchgate.net/publication/367476431_An_Overview_of_Advancements_in_Lie_Detection_Technology_in_Speech)
- Artificial Intelligence based Approach to Analyze the Lie Detection using Skin and Facial Expression - (https://www.researchgate.net/publication/376983308_Artificial_Intelligence_based_Approach_to_Analyze_the_Lie_Detection_using_Skin_and_Facial_Expression)
