Lablinc v71 23

SCR was measured continuously at 100 Hz using a pair of disposable, pre-gelled 8-mm Ag/AgCl electrodes (Biopac Systems) attached to the palm of the non-dominant hand. The electrodes were connected to an isolated skin conductance coupler (LabLinc v71–23, Coulbourn Instruments). The skin conductance module was further connected to a 16-bit AD converter (National Instruments, NI-6221), which digitized the raw analogue SCR signal. Offline data extraction was completed with PSPHA^{27 (link)}. SCR amplitude was determined by subtracting the average of a 2-s baseline (prior to stimulus onset) from the maximum response in a 0–7 s window following stimulus onset. This is an established approach for calculating SCR and has been extensively used in the past in our lab as well as others^{17 (link),28 (link)–35 (link)}. All responses were kept in the analysis, and SCR data were Z-transformed analogously to FPS responses.

SCR was recorded using a pair of disposable, pre-gelled 8-mm Ag/AgCl electrodes (Biopac Systems, Goleta, CA, United States) attached to the palm of the non-dominant hand. The signal was measured at 200 Hz with an isolated skin conductance coupler (LabLinc v71-23, Coulbourn Instruments). The raw analog signal was digitized by a 16-bit AD converter (National Instruments, NI-6221). Offline data extraction was completed with MATLAB. SCR amplitude was determined by subtracting the average of a 2-s baseline (prior to stimulus onset) from the maximum response in a 0–7 s window following stimulus onset. All responses were kept in the analysis, and SCR data were Z-transformed analogously to FPS responses. A technical problem with our SCR module during the last three months of testing affected the data of 9 participants, and rendered them unusable. Due to the uneven sample distribution this caused in our data, SCR analyses will be reported only in the supplement.