There are lot of disadvantages of using lie detection in the field of investigation:
Accuracy: One of the main criticisms of lie detection methods is that they are not consistently accurate. For example, polygraph tests, which measure physiological responses to questions, can produce false positives (incorrectly identifying a person as deceptive) or false negatives (incorrectly identifying a person as truthful). This means that investigators may make decisions or take actions based on inaccurate information.
Bias: Some research has suggested that lie detection methods may be prone to bias, meaning that they may be more likely to identify certain groups of people as deceptive more frequently than others. For example, there is evidence that polygraph tests may be more likely to produce false positives for certain populations, such as racial and ethnic minorities or people with mental illnesses.
Inconclusive Results: In some cases, lie detection methods may produce inconclusive or ambiguous results, which can make it difficult for investigators to make decisions or take action.
Ethical Concerns: The use of lie detection methods may raise ethical concerns, particularly if they are used in ways that are coercive or intimidating. For example, some people may feel pressured to take a polygraph test or may feel that their rights are being violated if they are required to undergo such a test.
Legal Admissibility: In many jurisdictions, the results of lie detection methods are not admissible as evidence in court due to concerns about their reliability and accuracy. This means that even if investigators believe that someone is being deceptive, they may not be able to present this information in court.
Overall, while lie detection methods can be a useful tool for investigators, it is important to recognize their limitations and to use them carefully and ethically.