Write a short note on define polygraph test. Elucidate three phases of polygraph examination.

Polygraph Test: Definition and Phases of Examination

The polygraph test, commonly known as a lie detector test, is a psychological assessment tool used to measure physiological responses associated with deception. It is based on the premise that when individuals lie, they experience physiological changes such as increased heart rate, sweating, and changes in blood pressure, which can be detected and recorded by the polygraph machine.

1. Definition:
The polygraph test involves monitoring multiple physiological indicators, typically including heart rate, blood pressure, respiration rate, and skin conductivity, while the individual being tested answers a series of questions. The polygraph examiner interprets changes in these physiological responses to determine whether the individual is being deceptive or truthful in their responses.

2. Phases of Polygraph Examination:

a. Pre-Test Phase:
The pre-test phase involves an initial interview between the polygraph examiner and the individual being tested. During this phase, the examiner explains the purpose and procedures of the polygraph test, discusses the relevant questions to be asked during the examination, and establishes rapport with the individual. The examiner also collects background information about the individual's medical history, psychological state, and relevant details about the issue being investigated. Additionally, the examiner may conduct a practice or "stimulation" test to familiarize the individual with the polygraph equipment and establish baseline physiological responses.

b. In-Test Phase:
The in-test phase begins with the administration of the polygraph test, during which the individual is connected to the polygraph machine, and physiological sensors are placed on their body to monitor their responses. The examiner asks a series of relevant, irrelevant, and control questions while observing the individual's physiological reactions. Relevant questions pertain directly to the issue under investigation, while irrelevant questions serve as neutral stimuli to establish baseline responses. Control questions are designed to elicit physiological reactions from both truthful and deceptive individuals, allowing the examiner to differentiate between truthful and deceptive responses based on the pattern of physiological changes observed.

c. Post-Test Phase:
Following the administration of the polygraph test, the post-test phase involves the examiner analyzing the data collected during the examination to determine the individual's truthfulness or deception. The examiner evaluates the individual's physiological responses to each question and compares them to established baseline levels. Based on the patterns of physiological arousal observed, the examiner renders an opinion regarding the individual's truthfulness or deception. The results of the polygraph examination may be used to inform further investigation or decision-making processes, although the reliability and validity of polygraph testing have been the subject of considerable debate within the scientific community.

In conclusion, the polygraph test is a psychological assessment tool used to measure physiological responses associated with deception. The three phases of the polygraph examination include the pre-test phase, in which background information is collected and rapport is established; the in-test phase, during which physiological responses are monitored while the individual answers questions; and the post-test phase, in which the examiner analyzes the data and renders an opinion regarding the individual's truthfulness or deception. While the polygraph test is widely used in certain contexts, its reliability and validity remain controversial, and it is not universally accepted as a scientifically validated method of detecting deception.