So Apple just announced a single lead ECG in the new Apple Watch. From the presentation it appears that they are using a skin contact electrical sensor in the back of the watch, and a corresponding closure of the circuit with a finger from the opposite hand on the crown.
My question is whether this could also be used for galvanic skin response (ie. skin resistance that varies with moisture in the skin - see below). My guess is hopefully - looking at the picture (halfway down the page on the apple site below) it appeared there are two halves to the sensor on the back of the watch - which would create an immediate circuit.