TITLE: Inducing Psychosocial Stress in the Laboratory: A Study Protocol for the Trier Social Stress Test (TSST)
AUTHORS: Johannes Bodo Heekerens

[DESCRIPTION]
This  protocol details about a laboratory session aiming at inducing psychosocial stress in the laboratory using the Trier Social Stress Test (TSST). During the laboratory session participants report affect and dissociative states eight times. Heart rate, electrodermal activity, and respiratory rate are assessed continuously. Blood pressure is measured eight times and eight salivary samples are taken to determine cortisol levels.

[BEFORE_START]
Participants should have at least 60 minutes resting time upon arriving at the laboratory before the laboratory session
begins to stabilize physiological responses, which may vary across participants. Participants are asked to abstain from brushing or flossing their teeth, smoking, using substances, drinking alcohol or caffeinated beverages, engaging in physical exercise, and eating during this time.

[GUIDELINES]
Detailed guidelines on the implementation and execution of the Trier Social Stress Test are available here:
Kirschbaum, C., Pirke, K. M., & Hellhammer, D. H. (1993). The 'Trier Social Stress Test': A tool for investigating psychobiological stress responses in a laboratory setting. Neuropsychobiology, 28(2), 76–81. https://doi.org/10.1159/000119004
Linares, N. F., Charron, V., Ouimet, A. J., Labelle, P. R., & Plamondon, H. (2020). A systematic review of the Trier Social Stress Test methodology: Issues in promoting study comparison and replicable research. Neurobiology of Stress, 13(5), 100–235. https://doi.org/10.1016/j.ynstr.2020.100235

[STEPS]
SECTION: Before the TSST
1. Before the TSST, the investigator shows and explains to the subject the devices for the assessment of heart rate (Vivalink ECG Patch), electrodermal activity (Empatica Smartwatch), and blood pressure (iHealth BP Cuff). The subject is instructed to put the devices on. The investigator makes sure that the devices are functioning as intended and that data transmission is running.
SECTION: Step 1: Explain ECG and EDA measurements in everyday life
32. The blood pressure monitor is only for the upcoming laboratory examination and will be removed afterwards. However, we ask that you wear the ECG device and smartwatch in your daily life for one week after the lab test.  
32. You may take off the smartwatch and ECG device after 9:00 pm. If you do so, please put the devices back on before 09:00 am. It is very important that you wear the devices continuously between 09:00 and 21:00 if possible.
SECTION: TSST - Prepare Speech
6. The investigator brings the participant to a separate room. One female and one male (active and passive stressors) already sit in the room. They are instructed to maintain serious mood, not to speak, laugh or the like, possibly answer the greeting of the subject with a curt "hello", and not to avoid eye contact.
SECTION: TSST - Prepare Speech
7. The investigater reads the following instructions to the participant:
Your task now is to give a speech to this committee for an application. You're about to have 5 minutes here to prepare for this speech. You can take notes on this, but you must not use them during the speech. Imagine that you have applied for a job that fits your previous career and that you have been invited to interview there, or that you are applying for a promotion that means more money, more responsibility and more interesting tasks for you. You are expected to give a free speech. You are required to explain to the committee in 5 minutes why you believe you are the best candidate for this position. To do this, stand behind the microphone after your preparation time so that your voice is recorded. Note that you will also be recorded by the camera. The devices are used for later voice and behavior analysis. Committee members are trained in behavioral observation and will take notes during the speech. Don't be alarmed by this. You should try to make the best impression possible and embody the applicant's role as best you can during the speech. The committee reserves the right to ask further questions if any ambiguity arises. After your speech, which should last five minutes, the committee will give you a second task, which will also be explained by the committee This will again take 5 minutes. Do you have any questions?
SECTION: TSST - Prepare Speech
9. The active and passive stressor enter the room and sit down. 

Active stressor: "Your preparation time is over.  Please pause and take the next measurement"

Measurement (+10). Assessment of affective and dissociative states via m-path application. The participant is instructed to take a saliva sample (product: Sarstedt Salivette Cortisol). Blood pressure measurement in sitting position on the non-dominant arm.
SECTION: After the TSST
16. The investigator brings the participant to a separate room.
SECTION: TSST - Arithmetic Task
13. Active stressor: "We will now explain the second task to you. This is an arithmetic task. You are to calculate backwards to zero in steps of 13 as quickly and correctly as possible. You will start at 1022. If you miscalculate, we will point this out to you and you will start again at 1022. Do you have any more questions? Please start now."

Passive stressor: restart stopwatch.

5 min 
SECTION: TSST - Arithmetic Task
13.1. If the participant miscalculates:

Active stressor: "Stop. 1022."
Active stressor: "Error. 1022."
SECTION: TSST - Arithmetic Task
13.2. The minimum speaking time is 5 minutes. The active and passive stressors are instructed to ignore objections. If necessary, the active stressor will repeatedly ask the participant to continue or restart the task.

Active stressor: "Start over at 1022."
SECTION: TSST - Arithmetic Task
13.3. If the participants looks at the ceiling or elsewhere in the room:

Active stressor: "Look at the camera, please!"
(when asked, say that looking to the camera is necessary for sufficient video recording)
SECTION: TSST - Arithmetic Task
13.4. If the participants speaks quietly:

Active stressor: "Please speak up!" 
(when asked, say that speaking loudly is necessary for sufficient audio recording)
SECTION: TSST - Arithmetic Task
13.5. In case of severe arithmetic difficulties, reinforcement by affirmative nodding. If necessary the task will be modified:

Active stressor:  "We'll change the task a little bit. Now calculate backwards in steps of 7. Start again at 1022."

If this still is too difficult, ask to add 7s.
SECTION: Before the TSST
3. The investigator then instructs the participant to use the m-path experience sampling application on the participant's smartphone to enroll in a survey repeatedly assessing affective and dissociative states. The participant is informed that the accuracy of the information is very important for the research project, and that questions are to be answered as it is in the current moment. 
SECTION: Before the TSST
4. Measurement (-10). Assessment of affective and dissociative states via m-path application. The investigator instructs the participant to sit down and take a saliva sample (product: Sarstedt Salivette Cortisol). Meanwhile, first blood pressure measurement in sitting position on the non-dominant arm.

10 min
 
SECTION: Before the TSST
2. It is explained to the participant that saliva samples will be taken during the laboratory session and that the samples will be used to measure cortisol levels.
SECTION: TSST - Deliver Speech
10. Active stressor: "Now come forward. (Pause) Stand behind the microphone on the floor marker (cross) and begin your presentation when the recording equipment is turned on."

Passive stressor: turn on camera / recorder, start stopwatch.

Active stressor: "Please start your presentation now."

5 min 
SECTION: TSST - Prepare Speech
8. The investigator, the active, and the passive stressor leave the room.

5 min 
SECTION: TSST - Deliver Speech
11. After 5 minutes, the active stressor says: "That should be enough here for now. We will explain the second task to you in a moment."
SECTION: TSST - Deliver Speech
12. Active stressor: "Please pause and take the next measurement"

Measurement (+15). Assessment of affective and dissociative states via m-path application. The participant is instructed to take a saliva sample (product: Sarstedt Salivette Cortisol). Blood pressure measurement in sitting position on the non-dominant arm.
SECTION: TSST - Deliver Speech
10.1. During the presentation, the active and passive stressors are instructed to seek and maintain eye contact with the subject, alternate taking notes and looking up to the subject, remain silent for at least 15 seconds during pauses in the subject's speech, not to respond to questions from the subject, but point to the task and that everything else will be clarified after the test, let the subject speak freely for as long as possible, and to make sure that the subject talks about her personality, and does not present professional qualifications or the like.
SECTION: TSST - Deliver Speech
10.2. If necessary, the active stressor intervenes:
"We already have your resume/credentials, please continue to tell us about your personal attributes."
"Please talk about your negative qualities".
SECTION: TSST - Deliver Speech
10.3. After 3 minutes the active stressor may ask:
"Why do you think you, of all people, are particularly suited for this ...?"
"Why are you more suitable than other applicants?"
"What qualities of yours tend to make you unsuitable for the job?"
"What leadership qualities do you possess?"
"Describe for us any other ... , that you have done or could do."
"How do you feel about teamwork?"
"Where do you see your position on a team?"
"Think about your last failure. How did you handle it?"

If these questions are too difficult, the active stressor may ask:
"Explain how your hobbies relate to ... ."
"What other interests do you have?"
"Describe for us a normal day in your life."
"Explain why it is important for you to perform."
"What do you think of the statement: 'A bird in the hand is worth two in the bush'?"
"Do you consider yourself a person who cares about his independence?"
"Do you think it's important to develop throughout your life?"
"How do you feel about friends?"
SECTION: TSST - Deliver Speech
10.4. The minimum speaking time is 3 minutes. The active and passive stressors are instructed to ignore objections. If necessary, the active stressor will repeatedly ask the participant to continue speaking.

"You still have time. Go ahead."
"Your speech time is not over yet."
SECTION: TSST - Arithmetic Task
14. After 5 minutes, the active stressor says: "Thank you very much. The interview is now over. Please take a seat and wait for the interviewer."

Passive stressor: Switch off audio and video recorders.
SECTION: TSST - Arithmetic Task
15. Active stressor: "Please pause and take the next measurement"

Measurement (+20). Assessment of affective and dissociative states via m-path application. The participant is instructed to take a saliva sample (product: Sarstedt Salivette Cortisol). Blood pressure measurement in sitting position on the non-dominant arm.

The committee leaves the room and the investigator enters the room.

10 min
SECTION: After the TSST
17. The investigator instructs the participant: "Please take the next measurement"

Measurement (+30). Assessment of affective and dissociative states via m-path application. The investigator instructs the participant to take a saliva sample (product: Sarstedt Salivette Cortisol). Blood pressure measurement in sitting position on the non-dominant arm.

10 min
SECTION: After the TSST
18. The investigator instructs the participant: "Please take the next measurement"

Measurement (+40). Assessment of affective and dissociative states via m-path application. The investigator instructs the participant to take a saliva sample (product: Sarstedt Salivette Cortisol). Blood pressure measurement in sitting position on the non-dominant arm.

10 min
SECTION: After the TSST
19. The investigator instructs the participant: "Please take the last measurement"

Measurement (+50). Assessment of affective and dissociative states via m-path application. The investigator instructs the participant to take a saliva sample (product: Sarstedt Salivette Cortisol). Blood pressure measurement in sitting position on the non-dominant arm.
SECTION: Before the TSST
5. Measurement (0). Assessment of affective and dissociative states via m-path application. The investigator instructs the participant to take a saliva sample (product: Sarstedt Salivette Cortisol).  Blood pressure measurement in sitting position on the non-dominant arm.