Page 179 - Demo

Embodied Facial Emotion Processing in Autism and Social Anxiety1776Upon completion of the first task, the electrodes were removed from the participants%u2019 faces, and the second subtask (emotion labelling) commenced. All 40 video sequences were once again presented, totaling three viewings per participant. When the video clip disappeared, participants were asked to judge the displayed expression. Specifically, we asked the following questions: (a) %u201cWhat type of expression was exhibited by the person in the video?%u201d; (b) %u201cHow confident are you in your judgment?%u201d (ranging from %u201cnot confident at all%u201d to %u201cvery confident%u201d); and (c) %u201cHow emotionally intense was the expression portrayed in the video?%u201d (ranging from %u201cnot intense at all%u201d to %u201cvery intense%u201d). Participants used horizontal sliders with invisible values to indicate their responses, ranging from 0 to 100 with increments of 10. The second subtask lasted approximately 10 minutes. MeasurementsFacial Electromyography (fEMG)Following the guidelines of Fridlund and Cacioppo (1986), we applied reusable 4 mm Ag/AgCl surface electrodes on the left side of the participants%u2019 faces to measure facial electromyography (fEMG). Two electrodes were placed over the Corrugator Supercilii region (referred to as %u201ccorrugator%u201d hereafter) to measure facial muscle (de-)activations that form part of mimicry patterns, which have been described for happy, sad, fearful, and angry expressions (K%u00fcnecke et al., 2014). As another part of the facial mimicry pattern of happy expressions, facial muscle activations over the Zygomaticus Major region (referred to as %u201czygomaticus%u201d hereafter) were measured with two additional electrodes. The ground electrode was applied on the top of the forehead. A Biopac MP160 system combined with a BioNomadix 2 channel wireless EMG amplifier was used to transmit and amplify the signals, which were recorded in AcqKnowledge 5.0 (Biopac Systems Inc, 2009) with a sampling rate of 1000 Hz. Initial data inspection and preprocessing was performed in the PhysioData Toolbox v.0.6.3 (Sjak-Shie, 2019), including rectification, filtering (28 Hz high cut-off filter, 500 Hz low cut-off filter and 50 Hz notch filter) and smoothing (Boxcar filter with 100ms window size). Based on the initial data inspection and the notes that had been taken during the recordings, corrugator data of six participants and zygomaticus data of five participants were entirely excluded due to poor data quality. Furthermore, the time-locked videos belonging to each datafile were carefully inspected for perturbations simultaneously with the EMG data recordings, and trials with visible effects on the data during stimulus presentation were noted for exclusion (corrugator: 277 trials,