Senior Scientific Officer-II, CFSL/CBI, New Delhi
Online published on 5 October, 2016.
Card test are meant to reassure innocent/Truthful subjects. However at the same time card test provoke greater anxiety in deceptive subjects. Card test are used to increase the reliability of the test, increase the faith of innocent person in the technique and helps an expert to know the depictive pattern of the subjects.
The lie detection procedure uses recording of physiological functions such as heart rate, respiration rate, blood pressure, and galvanic skin resistance. The subject is presented with not too long questions to which he is instructed to answer by ‘Yes” or “No”. There are variations in the manner in which questions are put across and the manner by which the subject must answer. Physiological responses are expected to be present when the subject intentionally tells lies to the questions.
In card test, the subject is asked to select a number from in between 1–5 and then the subject is asked 3–5 times: “is the number is 1?”, “Is the number is 2?, etc. the subject is instructed to lie intentionally to each question, even for the number the subject has selected. After asking the questions, the subject is told by the examiner which number he had selected and intentionally lied upon.
