Final answer:
It is true that the electrical resistance of the skin, which is affected by sweating, is measured using a galvanometer. This measurement is part of a polygraph test, which records physiological responses to assess emotional arousal. However, the accuracy of polygraphs to detect lying is contested.
Step-by-step explanation:
True, the electrical resistance of the skin associated with sweating that accompanies emotional arousal is indeed measured by a galvanometer. When a person experiences emotional arousal, the sympathetic nervous system is stimulated, which can lead to physiological changes, such as sweating. The presence of sweat on the skin increases its electrical conductivity by lowering the resistance. This change in resistance can be detected using a galvanometer as part of a polygraph test, which measures various physiological responses including skin conductivity, a concept known as electrodermal activity (EDA).
The galvanometer in a polygraph setup is sensitive enough to detect even small changes in electrical resistance caused by sweating. However, it is worth noting that while polygraphs are commonly used, the validity and accuracy of polygraph tests are widely debated. There is no consistent evidence that specific physiological responses, such as those measured by galvanometers, are uniquely indicative of deceit.