Subjective Stress.
State Anxiety. State anxiety will be evaluated using the state scale of the State Trait Anxiety Questionnaire (STAI; Spielberger, 1983, French version: Gauthier & Bouchard, 1993).
It includes 20 items concerning the current emotional intensity at that moment, using a 4-point Likert scale ranging from 1 (not at all) to 4 (very much). A score is computed by summing the items. Scores range from 20 to 80, with higher values indicating greater anxiety. The scale shows good internal consistency and test-retest reliability in different samples (Barnes et al., 2002).
Stress Item. Based on previous research (Becker et al., 2019; Lesage et al., 2012; Luettgau et al., 2018; Paszkiel et al., 2020), the perceived stress item (“Right now, how stressed do you feel?”) will be measured along a visual analog scale ranging from 0 (“not stressed at all”) to 10 (“extremely stressed”).
Stress Appraisal. We will administer the Primary and Secondary Appraisal Scale (PASA, Gaab et al., 2005). The wording of the items will be modified to match the context of the MAST (e.g., replacing “jury” with “experimenter”). The scale is composed of 16 items on a scale from 1 (totally disagree) to 6 (totally agree). It measures threat (e.g., “This situation scares me”), challenge (e.g., This task challenges me”), self-efficacy (e.g., “In this situation I know what I can do”), and control expectancy (e.g., “It mainly depends on me whether the experimenter judges me positively”). We will obtain primary and secondary appraisal scores by combining the scores from the first two and last two, respectively. The four factors have shown good internal consistency (e.g., from .60 to .83; Wirtz et al., 2006).
Repetitive Thinking Processing Modes. The State Repetitive Thinking Questionnaire (SRTQ; Philippot, 2019) will capture state negative repetitive thinking. Individuals will rate the extent to which they are having 10 specific thoughts in the preceding minutes, on a scale from 0 (“totally disagree”) to 4 (“totally agree”). We will focus on the Concrete-Experiential (3 items, e.g., “I am focused on what I am concretely experiencing now”) and Abstract Evaluative (4 items, e.g., “I wonder why I react like this”) processing modes.
Emotion Regulation. The Emotion Regulation Questionnaire (ERQ; Gross & John, 2003, French version: Christophe et al., 2009) will measure participants’ tendencies for reappraisal (six items, e.g., “When I was faced with the stressful situation, I made myself think about it in a way that helped me stay calm”) and suppression (four items, e.g., “I controlled my emotions by not expressing them”). The wording was modified to evaluate the strategies implemented during the stressor, ranging from 1 (not at all) to 7 (completely). Previous studies demonstrated adequate internal consistency (reappraisal, α = .76, and suppression, α = .72, Christophe et al., 2009).
Physiological Stress. The Mindware Mobile Recorder (Mindware Technologies, LTD) will be used to measure heart rate, skin conductance, and respiration at a sampling rate of 500 samples per second. Three Electrocardiogram electrodes (45mm, Ag/AgCl, liquid gel, MedCat) will be placed according to Mindware Technologies protocols (seehttps://support.mindwaretech.com/training/): one on the right collarbone and two on the last two ribs on both sides. Respiration will also be measured using a belt. In line with the Society for Psychophysiological Research Ad Hoc Committee on Electrodermal Measures (SPRAHCEM, (2012), electrodermal activity will be measured using disposable finger electrode strips (Ag/AgCl, MedCat) placed on the distal phalanges of the left major and index fingers and filled with Isotonic Electrode Gel (0.05 molar NaCl paste, Biopac).
These physiological measures will be collected using the BioLab Acquisition Software (V3.4.1). Systolic and diastolic blood pressure will be event-based, measured using the oscillometer method with the Omron M6 Comfort (HEM-7360-E, Omron Healthcare Co., Ltd; for more information see Topouchian et al., 2014) in sitting position (Shapiro et al., 1996). The M6 Comfort takes three consecutive 30-second readings.

Procedure

General Procedure

The study will be divided into three successive parts. It will begin with the signing of an informed consent form and the completion of online questionnaires before one’s visit to the laboratory. These will include sociodemographic items, as well as validated questionnaires evaluating chronic stress (PSS-10; Cohen et al., 1983).
Then, participants will come into the lab for a two-hour visit composed of cognitive testing followed by an acute stress induction. Participants will take a 10-minute break between the two sessions to allow for acclimatization (Shapiro et al., 1996). They will be able to hydrate, use the restroom, and complete a HRV screening checklist (Laborde et al., 2017). This questionnaire will help ensure that participants have avoided alcohol and strenuous physical activity for the previous 24 hours, as well as caffeine, food, and smoking for the last two hours (Jennings et al., 1981; Shapiro et al., 1996). They will provide their sleep and wake times and confirm whether they adhered to their usual sleep routine (Labuschagne et al., 2019).
Participants’ weight and height will be measured before the stress induction. The lab will be windowless, temperature-controlled, and electrically shielded to minimize any influences on psychophysiology measures (Shapiro et al., 1996, SPRAHCEM, 2012).

Acute Stress Induction

Acute stress will be induced using the validated Maastricht Acute Stress Test (MAST; Smeets et al., 2012; see Figure 1 for the overall procedure). Participants will first relax for five minutes, while heart rate, skin conductance, and respiration are continuously measured. Blood pressure will then be obtained, while participants complete the state items of the STAI (Spielberger, 1983) and a perceived stress level item (Becker et al., 2019).
The MAST procedure includes an anticipation, stress, and recovery phase. During the anticipation phase, participants will read through the MAST instructions using PowerPoint 2016 (provided by Tom Smeets, Smeets et al., 2012) and ask any questions. Then, they will complete the stress item, as well as questionnaires evaluating primary appraisal, emotion regulation, and repetitive thinking mode. During the stressphase, participants will alternate immersing their right hand in ice-cold water and performing a mental arithmetic task (serially subtracting 17 from 2043). Water and arithmetic trials will be exactly 90 and 45 seconds, respectively. The experimenter will be dressed in a white lab coat and will maintain a neutral attitude. A video camera will also be placed in front of the participant to record their facial expressions. Participants will be informed that their facial expressions throughout the MAST will be analyzed by a research team. Following the initial 12 minutes of the MAST, participants will complete the questionnaires again (see Figure 1), and blood pressure will be measured once more.
Upon completing the scales, participants will be informed that the task is finished and will be given a 10-minute recovery phase to relax. They will then complete the STAI and stress items, and we will measure their blood pressure. Participants will be fully debriefed about the study and financially compensated with 20 euros.
For a manipulation check, a control group will take part in a modified version of the MAST (Placebo-MAST, Smeets et al., 2012). Participants will place their hand in lukewarm water and perform a simple counting task at their own pace. All elements of evaluation (white lab coat, camera, or negative feedback for errors in calculations) will be removed.