SCRs were measured by two disposable carbon fiber electrodes attached between the first and second phalanges of the second and third digits of the left hand (EL509, BIOPAC Systems, Inc., Goleta, CA). The electrodes were connected to a BIOPAC Systems skin conductance module (GSR100C) and skin conductance was continuously sampled at a rate of 1000 samples per second, amplified, and stored on a Dell laptop computer for offline analysis using AcqKnowledge 4.1 software (BIOPAC Systems, Inc.). The recorded waveforms were low pass filtered using a Blackman window (cutoff frequency = 125 Hz) and mean value smoothed over 100 adjacent data points prior to scoring.
