2.2. Procedure
Two visits to the laboratory were scheduled for participants, with a two-week gap between each session. At the first visit, the participants finished a demographics questionnaire, the Beck Depression Inventory-II (BDI-II), and the State-Trait Anxiety Inventory (STAI-T). Baseline measurements of cognitive flexibility were also administered using the Wisconsin Card Sorting Test (WCST) to keep any group differences from influencing experimental results.
To reduce cortisol and EBR changes, the second laboratory visit was arranged between 14:00 and 18:00 (Barbato et al., 2000). Upon arrival, participants measured spontaneous EBR and pupil diameter for 3 min during the baseline state (Ocular 1). They then completed the Remote Association Task (RAT) and Alternative Uses Task (AUT) tests before the acute stress induction. Following the completion of the Montreal Imaging Stress Tasks (MIST) or the control task, Ocular 2 was assessed while the participant was continuously thinking about either an angry or a calm memory. Subsequently, participants performed the post-test WCST and the post-test AUT.
Twenty min after the end of AUT, Ocular 3 was administered for 3 min. After Ocular 3, the participant started to complete the post-test RAT. Spirit-10 wireless telemetry biofeedback instruments (Mind Media, B.V. Netherlands) were used to measure heart rate throughout the experiment. Electrodes were applied to the chest for an electrocardiogram (ECG), and BioTrace+ was used to evaluate the ECG data at a sample rate of 2048 Hz. The spontaneous EBR and pupil diameter were measured during the MIST task and Ocular tasks. The saliva samples were taken at the time points of T, and the STAI-S and PANAS were evaluated at the time points of S (see Fig. 1).