Polygraph test, exam explained
The polygraph test process | Steps of a lie detector exam
Polygraph test and polygraph are often used as a synonym, it is important to distinguish among these concepts. There cannot be a polygraph test without a polygraph instrument, however, to perform a professional lie detection test the examiner needs to understand the process and how to use the instrument in such a way that she/he can obtain the information she/he is looking for.
We will try to explain the process of a common polygraph detection of deception exam. However, the polygraph can also be used for other purposes.
Polygraph test types
The first thing one needs to understand is that there are different types of tests that can be performed. The instrument can be used to obtain information from the memory of an individual. Used under the right circumstances diverse things can be explored.
We could distinguish between two main types:
- Memory tests
- Emotional stress tests
The first type, memory exams explore for knowledge to certain elements or information by an individual while the latter analyzes the threat a certain issue causes in a person.
Memory tests are used for example investigate if a person knows where a certain object is, like for example the weapon of the crime.
Emotional stress tests are the most popular kind of tests since they pretend to find out if somebody is telling the truth of deceiving about a certain issue. Again even within the detection of deception tests exist distinctions, which are dealt with in the next paragraph.
Lie detection tests
Lie detection tests are the most popular exams and most know to the general public. However, within this segment of application, a variety of fields can be explored.
We could distinguish between:
- Screening tests
- Evidence/Specific exams
Screening polygraph tests are used to filter or screen people. This type of application is most used in human resources. The selection or recruitment process in an organization is a natural application. This type of test makes part of a thorough vetting process.
These exams, however, can also be applied to check the behavior of individuals on certain issues like for example the conditions of parole.
Evidence exams also referred to as specific tests are performed to probe the testimony of an individual about a specific issue. These are the tests general public normally refers to when talking about polygraph tests.
It is important to understand that when thinking about using this solution for business or personal life environment it is important to understand the process. The best way to proceed is to explain to the examiner what the intentions/objective are/is. An experienced examiner will design the best solution for each specific case.
For more information please contact a B.E.A.R. FORENSICS representative.
How does it work?
As mentioned before, there is a broad variety of polygraph tests. However, even if the objective of an exam differs, the process is more or less the same no matter the technique employed.
A normal lie detection test will follow the following steps:
- Consent form signature
- Explanation of the instrument and test process
- Pre-test interview about the issue under investigation
- Data collection phase also called In-test phase
- Analysis of the collected data
- Elaboration of the findings and report
A normal test lasts somewhere between 2 and 4 hours depending on the test, technique, and complexity of the issue.