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Lie Detection: A Forensic Adventure


What is lie detection?

Detection of lies is an evaluation of a verbal statement with the objective of revealing a possible intentional deception.

What is lie detection in the Forensic context?

In order to investigate and solve criminal cases, lie detection technology has been increasingly used. In’ psychology and law,’ which in turn is one of the main areas of applied psychology, lie detection is a major theme. Indeed, in police investigations, court trials, border control interviews, intelligence interviews, and so on, it is not difficult to understand why it is important to know whether someone is lying or telling the truth. Numerous lie detection tools have been developed by psychologists and practitioners to aid lie detection. These tools range from observing behaviour, analysing speech, and measuring peripheral physiological responses to recording brain activity to the full range possible.

History and Background of Lies and Lie detection

No one can ever tell who, where, or why, yet we can be assured of the vocabulary used in the first deception, terms initially meant to expose and justify rather than confuse and hide. It has grown into a fine art over time and is now ubiquitous, so much so that the term euphemism is understood by most people. A German philosopher, Fredrich Nietzsche, argues that lies’ tenders are not relativism, but a mechanism for discriminating between truth and falsehood, rooted in the understanding that language is too porous a vessel for keeping true facts beyond the anthropocentric. In the recognition, creation and articulation of “truth,” he shows this transfiguration of physical evidence into an abstract definition. Nietzsche implies that our purest interaction with truth consists in breaking away from the language pit and standing in total attentive presence with the reality of what is before us, beyond classification, beyond explanation, beyond constriction into the concept.

People have been involved for decades in finding lies. The connection between lying and physiological activity has drawn the most interest in history. For example, the Chinese used to compel accused liars to chew rice powder in 1000 BC and then spit it out and the individual was judged to have been dishonest if the rice powder was dry. In North Bengal, India, the accused was told to prove his innocence by applying his tongue to a red-hot iron nine times, based on the same dry-mouth assumption. This ordeal was further compounded by the fact that the convict was told to bear the red-hot iron in his hands. Trovillo offers a variety of anecdotal evidence of historically used lie-detecting measures, but do not provide scientific underpinnings or tests. It is possible to view Münsterberg as one of the leading researchers involved in identifying lies. Münsterberg, his work, contains a wealth of still-relevant theories on lie identification. It was William Moulton Marston, a student from Münsterberg, who invented a lie detector system, today known as the polygraph. Physiological identification of lies with the polygraph was more developed in the first half of the 20th century and was widely used in the second half of the 20th century, particularly in the United States. Hundreds of thousands, maybe even millions of Americans, were checked annually at its height in the 1980s.

Modern lie detection

Historical approaches were non-scientific and may be erroneous. Perceptions that can often result in erroneous or wrongful perceptions, interpretations, or rulings. New scientific methods, however, are more effective since they are based on evidence and can replace the older testimony techniques. Polygraph, also known as Lie Detector, is a more commonly used and renowned popular research tool designed for the psychophysiological detection of deceit with its development in the 20th century. It is also regarded as an analysis of psychophysiological identification of deceit (POD). The Polygraph exam is based on the premise that the fear of identification is, and imprisonment prompts a person to be fooled by the real reality that Escort to emotional arousal that is further attempted to hide by “Defence mechanism, known as physiological”. In the Polygraph test, the machine senses, not lies, but indirect manipulation of feelings, only the behavioural changes that follow the sudden emotion of tension directly. Polygraph distinctly displays distinct body functions as well as some sudden changes in these functions (breathing, heartbeat, blood pressure, sweating, etc.).

Types of Lie Detection

  1. Polygraph- Usually, the instrument used to administer polygraph examinations consists of a physiological recorder that measures three autonomic arousal indicators: heart rate, blood pressure, breathing, and skin conductivity. Computerized recording devices are used by most examiners today.
  2. Cognitive Polygraph- Since controlling for personality variations, Tri-Con was able to differentiate between truth-tellers and liars. The precision of the grouping of liar-truth tellers hit 89%. Mean reaction times and accuracy in answers should be used to separate people who lie from those who say the truth.
  3. ERP & EEG- P300 is an electroencephalogram (EEG) derived brain wave that has recently been used as a novel information source for deception detection. The typical pathways from the autonomic nervous system are documented which involve physiological behaviour such as the rhythm of breathing, blood pressure, and conductance of the skin. The EEG, on the other hand, is a record of sequential, randomly shifting voltages, collected from the scalp surface in humans as a function of time. The random operation of the underlying cerebral cortex is expressed here. If a discrete trigger phenomenon (such as a light flash) happens as these shifting voltages arise, the EEG splits into a sequence of much larger peaks and troughs, called parts. This sequence of waves is considered a possible phenomenon-related event (ERP).
  4. Eye-tracking technique- Instead of calculating the emotional response of an individual to deception, eye-tracking technology tests the cognitive reaction of the person. The researchers log a variety of observations and do so as a subject answer on a computer to a series of true-and-false questions.
  5. Voice stress analysis- To measure and evaluate frequency variations in the responses of the subject that signify vocal tension, it utilizes a microphone plugged into a device. When the subject talks, each voice pattern is shown and numbered by the computer. An algorithm scores the results at the conclusion of the measurement.
  6. fMRI- Functional magnetic resonance imaging (fMRI) attempts to diagnose mendacity by seeing within the brain rather than monitoring peripheral distress metrics measured by a polygraph, such as changes in heartbeat, blood pressure or respiration. In addition to attracting hundreds of thousands of audiences, developers have been attracted by fMRI.
  7. Non-verbal behaviours- Nonverbal credibility appraisal analysis shows that the precision of witnesses in discriminating between genuine and false messages based on the behavioural displays of the sender hardly reaches the degree of chance. This compares with performance scores that are very high when using psychophysiological (e.g., polygraph) or verbal (e.g., CBCA) approaches. It is, however, argued in this paper that assumptions regarding the poor accuracy of reputation assessments based on the actions of senders are incorrect.
  8. Drugs- Forensic researchers use unique neuroscience methods in this test to figure out how the brain of a suspect knows information from a crime scene that the brain of an innocent victim has no experience of. Sensors are mounted to the suspect’s head during brain-mapping and he or she is forced to pose in front of a computer screen.


Uses of Lie detection

In security, screening, the primary aim of the polygraph test is to recognize people who constitute significant risks to national security. The purpose of putting this in the vocabulary of medical tests is to reduce the number of false-negative cases to a minimum (serious security risks who pass the diagnostic screen).

In Civil Cases, it may be used in:

  • Diagnostic, interventional & Rehabilitative

(Clinical Psychology)

 In Criminal Cases, it may be used in:

  • Investigative (Forensic Psychology)
  • Reformation by Reasoning & Rehabilitation (R&R) i.e., Neuro


Mental Status Examination

  • Competency
  • Custody evaluations

Disability evaluations

  • Detection of deceptions
  • Rendering diagnostic opinion regarding the honesty or dishonesty

Lie detection and Digital Forensics.

The two opposite sides of the same coin are called Steganalysis and steganography. Steganography attempts in plain sight to hide messages while steganalysis tries to detect their presence or to recover the encoded data even further. A great deal of attention was given to both Steganography and Steganalysis, especially by law enforcement.  Although cryptography is illegal or restricted in many nations, cybercriminals or cybercriminals are to stop getting arrested with encrypted incriminating information in their hands, even criminals use steganography extensively. In exposing illegal behaviour, it is also important to consider the ways in which communications can be encoded in a visual medium, in most cases in digital images, and knowledge of state-of-the-art methods to identify secret content. In use and use, digital image steganography is increasing. Over the last few years, several strong and robust methods of steganography and steganalysis have been presented in the literature.


Gaps in literature

The control question test can be effective as an investigation assist and as a question test. It does not pass a valid test as a method for causing confessions. The test is based on young, unplausible postulations that show prejudice toward innocent citizens and could also be defeated simply by increasing responses to control problems. Therefore, scientists, including members of the Society for Psychophysiological Studies, have unfavourable opinions on the procedure and are largely suspicious of the arguments presented by the polygraph promoter, with the required context to analyse the control issue test.


The standard of polygraph testing and studies has increased. Three-four decades in the past. Already, Polygraph serves as a feasible analysis instrument for investigation organizations that evoke.  Study to overcome the present shortcomings to increase the reliability of the exam for the polygraph. Given the fact that it would not be possible to raise the polygraph to the extent that it can be known as the Lie Detector, it seems to have the potential to become one of the strongest instruments for the overall objective of allowing investigation agencies to spot deceit. Its usage to assist in the investigation process by, for instance, the person who is involved is not so far away.


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