- This is the tool of modern forensics to catch the culprits and trace the criminals and decipher their modus operandi by administering hypnotics or similar drugs into the suspects.
- In the Narco Analysis Test, the subject’s imagination is neutralised by making him semi-conscious. In this state, it becomes difficult for him to lie and his answers would be restricted to facts he is already aware of.
- Experts inject a hypnotic like Sodium Pentothal or Sodium Amytal and the subject which is put in a state of Hypnotism is not in a position to speak up on his own but can answer specific but simple questions after giving some suggestions.
- This test is of great help in tracing a crime and finding some evidence, where no primary evidence is available.
- Truth serum is a drug used in narco-analysis that cause a person to become uninhibited and talkative, but they do not guarantee the veracity of the subject’s statement.
- People who are under the influence of truth serums enter a hypnotic state and speak freely about anxieties or painful memories. The subject’s imagination is neutralised when semi-conscious, making it difficult for him / her to lie and his / her answers would be restricted to facts of which he / she is aware.
Limitation: Such tests generally don’t have legal validity as confessions made by a semi- conscious person are not admissible in court. It states that subjects under a semi-conscious state do not have the mind set to properly answer any questions, while some other courts openly accept them as evidence.
- A polygraph (commonly known as a lie detector) is a device that measures and records several physiological variables such as blood pressure, heart rate, respiration and skin conductivity while the subject is asked a series of questions.
- The measurements are posited to be indicators of anxiety that accompanies the telling of lies. Thus, measured anxiety is equated with telling untruths.
- However, if the subject exhibits anxiety for other reasons, or can control his anxiety level voluntarily, a measured response can result in unreliable conclusions.
- A polygraph test is also questionably used as a psycho-physiological detection of deception (PDD) examination.
Limitation: Today, polygraph examiners use two types of instrumentation, analog and computerized. While some people believe that polygraph tests are reliable, there is little scientific evidence to buttress this claim. For example, while some claim the test to be accurate in 70% – 90% of the cases, critics charge that rather than a “test, the method amounts to an inherently unstandardizable interrogation technique whose accuracy cannot be established.
- Brain fingerprinting, invented by Dr. Lawrence Farwell, is a technique that measures recognition of familiar stimuli by measuring electrical brain wave responses to words, phrases, or pictures that are presented on a computer screen.
- The theory is that the suspect’s reaction to the details of an event or activity will reflect if the suspect had prior knowledge of the event or activity.
- This test uses the Memory and Encoding Related Multifaceted Electroencephalographic Response to detect familiarity reaction.
Ethical Consideration: The electrical potential of the human brain with relation to specific thoughts and feelings seem to some people to be highly invasive. However, such screening procedures might potentially be much more effective than polygraph screening, which has never been shown to have prevented an act of espionage.
This article for only instructional purpose.