While his colleagues were busy, the woman began to speak, "Chief Inspector Dean, before we conduct the polygraph test, I need to confirm—within the last twelve hours, have you consumed any stimulants such as cigarettes or cola?"
Dean shook his head. "After receiving the notice yesterday, Officer Carlo and I complied with the requirements."
Consuming stimulants before the test can lead to inaccurate polygraph results. Modern polygraph equipment works by measuring changes in pulse, breathing, and skin resistance to determine if someone is lying. Liars, when facing questioning, often experience psychological pressure. This can lead to anxious psychological and physiological reactions like increased breathing and heart rate, higher blood pressure, and elevated adrenaline levels, among other things. This is controlled by the body's autonomic nervous system, and by measuring these physiological changes, one can theoretically determine if a person is lying.
