Page 68 - Demo

Chapter 366Figure 1. (a) Visualization of the subtle cue stimuli for one stimulus identity. The respective neutral facial expression from the NimStim set of Facial Expressions (first; Tottenham et al., 2009) was manipulated by adding a blush (second), tears (third) or dilated pupils (last). (b) Trial structure of the Passive Viewing task (left) and the Emotion Labelling task (right).MeasurementsPupil size. Eyetracking data was recorded using a Tobii X2-60 eyetracker (sampling rate 60 Hz) to which event markers were sent via the presentation software. Filtering of the data as well as artifact identification and rejection were undertaken in the PhysioData Toolbox (Sjak-Shie, 2019) according to the guidelines described in Kret and Sjak-Shie (2019). EMG. Facial muscle activity related to the observation of emotional expression was measured over Corrugator supercilii and Zygomaticus major regions (in the following referred to as %u201ccorrugator%u201d and %u201czygomaticus%u201d). In total, five 4mm reusable AG/AgCl surface electrodes were attached on the participant%u2019s face: two over each region of interest in the left side of the face and one ground electrode on the centre of the forehead, just below the hairline, according to the guidelines by Fridlund and Cacioppo (1986). Data was recorded with the Dual Wireless EMG BioNomadix System (Biopac, 2000 Hz sampling rate). The initial preprocessing of the raw EMG data was performed in the PhysioData Toolbox (Sjak-Shie, 2019). Before rectification of the signal, a 28Hz high-pass FIR, a 200Hz low-pass FIR and a 50Hz (Notch) filter were applied to the EMG data.