The polygraph procedure centers on gathering data from a person’s physiological signals such as sweat production, changes in peripheral blood flow, and breathing patterns. By presenting questions and monitoring how the machine’s indicators respond, an examiner gains insight into which topics hold significance for the individual being tested. In clinical and investigative settings, two widely used frameworks guide the process. These approaches are described by researchers affiliated with the VB Psychophysiology Laboratory and the Shvyrkova Institute of Psychology at the Russian Academy of Sciences, who emphasize that polygraph data reflect internal relevance rather than simple truth-telling. At its core, the technique seeks to map which questions trigger stronger autonomic reactions and what those reactions reveal about engagement with the subject matter. Source attribution: VB Psychophysiology Laboratory and Shvyrkova Institute of Psychology, RAS.
There are two predominant testing paradigms employed in practice: the identification of sensitive information and the use of control questions. In the first approach, the examiner presents targeted questions about specific details of an event. For instance, in a theft scenario, questions might probe about sums of money, the tools used to gain entry to a safe, or particular medications or materials associated with the incident. The important point is that these questions are crafted to elicit meaningful physiological responses that can be compared against baseline measurements. When the indicators shift noticeably in response to these event-specific probes, the examiner interprets that change as evidence that the person assigns personal importance to the queried details. This pattern, in turn, is read as a potential indicator of involvement. Source attribution: VB Psychophysiology Laboratory and Shvyrkova Institute of Psychology, RAS.
However, a caveat remains: someone who happens to know intricate details of the incident can still reveal a strong reaction, which complicates interpretation. The alternative approach—control question testing—asks about the person’s actions in a direct but carefully phrased manner. An example is a direct inquiry such as whether the missing funds were taken from the safe. This kind of question is labeled a test question because it is designed to provoke a measurable response tied to the person’s reaction to the premise of the act. Neutral questions are also integrated, intended to be emotionally neutral and not expected to provoke a strong response, such as a verification about one’s own identity. The exact set of control questions is not fixed; it varies with the theoretical framework guiding the examination. The process involves comparing the relative strength of responses to verification questions and to control questions, enabling a reasoned conclusion about the likelihood of involvement. Source attribution: VB Psychophysiology Laboratory and Shvyrkova Institute of Psychology, RAS.
In practice, psychologists and polygraph experts use these methods as part of a broader approach to assessing truthfulness and memory under pressure. They acknowledge that physiological indicators are influenced by a range of factors, including anxiety, fear, fatigue, and even deliberate countermeasures. The goal is to interpret patterns of arousal in the context of the person’s overall presentation, the task demands, and the corroborating information available. While the technique has its advocates for highlighting inconsistencies and prompting further investigation, it also carries limitations that practitioners must navigate. The value of the polygraph lies in its ability to provide a structured, objective trace of physiological responses that, when combined with careful interview techniques and corroborating evidence, can inform decisions in both clinical and investigative settings. Source attribution: VB Psychophysiology Laboratory and Shvyrkova Institute of Psychology, RAS.