Electromyograph (EMG) electrodes (Ag-AgCl) filled with saline gel were attached to the participant's face on skin covering the orbicularis oculi muscle using a bipolar configuration (Fridlund & Cacioppo, 1986). The EMG signals were acquired and amplified with BIOPAC Systems (Goleta, CA) EMG100A Electromyogram Amplifier modules connected to a BIOPAC Systems MP100WSW bioamplifier. The data were recorded and displayed using BIOPAC Systems’ AcqKnowledge III data acquisition software (version 3.5.3), with a sampling rate of 1,000 Hz. A 10- to 500-Hz bandpass filter (Tassinary & Cacioppo, 2000) and a 60-Hz notch filter were used online. We scored the orbicularis oculi facial EMG signal in microvolts (μV) after the results were rectified and smoothed using a five-sample boxcar filter. Trials with clear movement artifact or excessive baseline activity were marked as missing.
