1. The problem statement, all variables and given/known data Question: "What does a polygraph test measure; skin resistance or conductance?" To me this is two sides of the same coin and it seems it must be measuring both. 2. Relevant equations 3. The attempt at a solution I thought that the person is acting as a resistor so I wrote down resistance, but the answer is conductance. I could just memorise the answer but I would like to understand why. I'm a psychology student so please speak slowly and without assuming any basic knowledge.