A Polygraph test is often referred to as a “Lie Detector Test” and is a test used to verify a person’s truthfulness.
The test is performed by a professionally trained polygraph examiner using a computerised instrument. The polygraph is a scientific instrument designed specifically to record physiological changes such as blood pressure, pulse, respiration and skin conductivity that occur in the human body whilst the subject answers a series of questions. The examiner looks for those changes consistent with deception and forms an opinion about your truthfulness.
The polygraph comprise of:
- Sensor that records respiratory activity.
- Measuring device that records sweat and gland activity.
- Sensor device that records cardiovascular activity.
- A motion sensor that monitors general movements that might interfere with test data.
A typical polygraph examination will include a period referred to as a pre-test interview, a chart collection phase and a test data analysis phase. During the pre-test, the polygraph examiner will complete required paperwork and talk with the examinee about the test, answering any questions the examinee might have. It is during this phase that the examiner will discuss the test questions and familiarize the examinee with the testing procedure.
During the chart collection phase the examiner will administer and collect a number of polygraph charts. The number of questions and the number of charts will vary, depending on the number of issues and technique employed.
Following this, the examiner will analyse the charts and render an opinion as to the truthfulness of the examinee. The examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to one or more questions presented during the test.