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The polygraph is the most well-known tool for detecting deception through psychophysiological means. The components of this machine detect and record changes in the body that aren't immediately visible to an observer. This recording is then interpreted by the technician. Prior to the introduction of this machine, however, investigators could only use a variety of experimental means and methods to detect deceit in a person. These were the forerunners of the scientific methods of detecting deception.
Hypnotism
Hypnotism
Friedrich Anton Mesmer, from whose name we derive the word mesmerize, pioneered this approach in 1778. His work was based on animal magnetism, which was shown to provide a healing effect on his audience.
The word hypnosis itself is derived from the Greek word, hypnos. It means sleep. While it is common in popular culture to depict someone undergoing hypnosis as being made to sleep, the name is actually a misnomer since the participant is really being forced into a reduced state of awareness while still being awake. This is why James Braid, a Scottish surgeon and one of the founders of modern hypnosis, attempted to retract the name when he realized that it had nothing to do with sleep, making the name rather deceptive.
Other famous personalities who studied hypnosis include Sigmund Freud, Albert Einstein, and Thomas Edison.
Initially, hypnosis was almost discredited because the work of Mesmer turned out to be inaccurate. However, it has been found that the phenomenon was only not explained well, but does exist. Currently, this technique is used by every branch of the military, professional athletes, and politicians. It was accepted by the American Medical Association in the 1950's.
The Word Association Test
The Word Association Test
This is a psychological method introduced by Sir Francis Galton in 1879. In this method, the subject is given a word and responds with the first thing that comes to mind. It is a highly-acclaimed subtle strategy that is said to be able to catch out liars.
Galton's experiments were later developed by Dr. Carl Gustav Jung, a Swiss psychologist and the founder of analytic psychology.
The Truth Serum
The Truth Serum
Dr. Edward Mandel House, a US physicist, diplomat, and confidential advisor to former US president Woodrow Wilson, pioneered the process. It involves the use of a drug called hyosine hydrobromide (Scopolamine) hypodermically given in repeated doses before delirium is induced. When interrogated in this state, subjects are said to be truthful.
This drug was first "discovered" by obstetrician Dr. Robert House. He observed that the drug would put patients into a state he called "twilight sleep." Under this state, patients readily delivered information. He theorized that this could then be used as a "truth-inducing drug" that could be used to interrogate criminal suspects and have them tell the truth. His experiments showed that disables subjects from lying as it keeps them from using the brain's thinking abilities.
Under international law, however, these drugs are deemed unconstitutional and immoral. Furthermore, they are classified as a form of torture. Nevertheless, it was reported in 2008 that this was used by Indian police interrogators to arrest the gunman responsible for the Mumbai attacks, demonstrating the continue use of so-called "truth-inducing substances."
Narco-analysis or Narco-synthesis
Narco-analysis or Narco-synthesis
This method is similar to the previously mentioned method wherein it involves the use of drugs, such as sodium pentothal, scopolamine, or sodium amytal, to induce different stages of anesthesia in the subject. The subject then becomes hypnotized during which the subject can become less inhibited and is more likely to disclose matters they wouldn't otherwise.
The major disadvantage of this method is that certain people can maintain their ability to deceive even when they become hypnotized, while others can become highly suggestible during questioning. Hence, you cannot really be certain what is really going on in your subject when using this method.
Additionally, an investigator with a false agenda might question a subject in such a way as to elicit incriminatory answers.
In the age of evidence-based medicine, this method is discredited as no study backed its claims.
The Psychological Stress Evaluator
The Psychological Stress Evaluator
The principle used in this method is the same as that used in the polygraph machine where it is said that the body behaves differently when the person is telling the truth from when a person is attempting to be deceitful. Except, instead of using the heart rate, pulse, electric activity, etc. of the body, the psychological stress evaluator (PSE) is based on voice analysis.
The video above is showing a voice analysis expert manually analyzing a recording. The PSE, on the other hand, is a machine, but it basically operates in the same way.
Intoxication
Intoxication
This method is similar to using the truth serum and narco-analysis in that it utilizes a drug in order to induce the "truth" from a subject. Once again, getting a subject drunk before questioning is based on the idea that people become truthful when they are in an altered state.
Methods of Detecting Deception Through Regular Police Work
Methods of Detecting Deception Through Regular Police Work
Once again, we circle back to the 5 wives and one husband. Or, WHO, WHAT, WHEN, WHERE, WHY, and HOW. These are the essential lines of questioning that investigators use to determine the 3 I's:
Information gathered through record check, surveillance, and intelligence check
Investigation done through interrogation and/or interview to obtain admission or confession
Instrumentation through the use of criminalistics processes
The third part is where we see the use of the polygraph - the modern method of detecting deception.
Supplemental Videos
Supplemental Videos
SciShow, The Science of Hypnosis
CrashCourse, Altered States: Crash Course Psychology #10
Psyched Substance, Are Drunk Actions ACTUALLY Sober Thoughts? What Science Says!
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