Why Don't Police Just Hook Criminals to a Lie Detector?
The use of lie detectors, or polygraphs, in the criminal justice system has been a topic of much debate. While the concept of using a lie detector to ascertain guilt or innocence may seem straightforward, several factors make this approach less than ideal. From the voluntary nature of the tests to their questionable reliability, there's a good reason why law enforcement doesn't use them as a standard tool in their arsenal.
The Voluntary Nature of Lie Detector Tests
One of the primary reasons why the police cannot force individuals to take a lie detector test is because these tests must be voluntary. The Constitution guarantees that an individual cannot be compelled to incriminate themselves. Therefore, if a suspect does not consent to taking a lie detector test, it would be unlawful for the police to force them to do so. This voluntary nature is essential to protect individual rights and uphold the principle of fairness in the criminal justice system.
The Reliability and Effectiveness of Lie Detectors
Another major issue with lie detectors is their unreliability. While polygraphs are designed to detect deception, they can often be defeated or made unreliable due to various factors. For instance, individuals with anxiety disorders may fail a lie detector test not because of guilt, but because of the physiological stress caused by the police interrogation process.
Moreover, the process of administering a lie detector test is not always straightforward. The suspects often undergo extensive interviews prior to the test, and the questions asked can be modified based on the suspect's responses. This means that polygraphs are not a foolproof method of detecting deception. Legal experts argue that even if a suspect fails a test, the results are not reliable enough to stand in court. In fact, the results of a polygraph are often seen as inadmissible in court, rendering them ineffective as a tool for securing convictions.
A Real-Life Example: Trivially Easy to Defeat
The unreliability of lie detectors is further illustrated by a famous case from the TV show Barney Miller. In one episode, one of the characters, Arthur Dietrich, was asked during a lie detector test where he lived. He responded with the nonsensical, "I come from a planet far, far away," and the lie detector did not indicate any deception. This posed a challenge for the lie detector test operator, who was unable to detect the obvious fib on such an absurd statement.
Years later, the author of this article had to take a lie detector test as part of a bonding process for a job. They asked the test operator if they could replicate the scenario from the TV show where the test fails. To their surprise, when asked the same question, and answering the same way, the machine again showed no deception. This experiment demonstrated the ease with which lie detectors could be deceived, highlighting their unreliability.
Why Aren't Lie Detectors Used More Frequent?
While lie detectors have their uses, such as providing valuable insights during extensive interviews, their high cost and time consumption make them impractical for everyday police work. For example, scheduling a polygraph test can take a significant amount of time. The process, which typically takes between one to three hours, can be cumbersome, especially when dealing with minor cases, such as the theft of a car stereo. It is not feasible for law enforcement to allocate so much time and resources for every minor infraction.
Conclusion
In conclusion, while lie detectors may seem like a straightforward solution to the problem of determining guilt or innocence, they are far from reliable and effective. The voluntary nature of lie detector tests, their susceptibility to being defeated, and their high cost make them unsuitable as a standard tool in law enforcement. Instead, the focus should be on improving interview techniques and other investigative methods that are more effective and reliable.