Trier Mental Challenge Test (TMCT)

Background

The Trier Mental Challenge Test (TMCT) is a computerized cognitive test to induce mental stress leveraging arithmetic tasks to be calculated under time pressure. It was originally designed by Clemens Kirschbaum and colleagues at the University of Trier, Germany, in 1991 as a specialized laboratory protocol to induce a reliable release of the stress hormone cortisol. Shortly after its introduction, the TMCT was integrated as a core component of the more broadly recognized Trier Social Stress Test (TSST), which Kirschbaum and colleagues formally established in 1993.

The Millisecond TMCT task is inspired by the procedural publication of Clemens Pruessner and colleagues (including Kirschbaum) from 1999 who used the TMCT to study the relationship between low self-esteem, induced failure and the adrenocortical stress response. Stress responses in the TMCT are induced by asking participants to solve arithmetic problems of five different difficulty levels within 5 seconds each. The difficulty levels are adaptive and based on performance. Points are earned for each correct response but decrease for every error made. The accumulated points are always visible on screen. Stress responses can be further increased by providing a visible timer.

Task Procedure

The TMCT runs arithmetic problems of five difficulty levels that all result in solutions ranging from 0-9. For example, level 1 problems are simple addition/subtraction problems (e.g. "3 + 6" or "10 - 7"); level 5 problems containing mixed operations (e.g. "4 + 14 - 5 * 3"). Participants get 5s to select the correct response from a circular response dial by mouse click or touch.

The test starts at level 1 and 30 start points. Each correct response increases the total points by one; each incorrect response decreases the total points by 1. The number of total points controls the level of problem difficulty:

1. Level 1 problems: below 36 points
2. Level 2 problems: 36-40
3. Level 3 problems: 41-45
4. Level 4 problems: 46-50
5. Level 5 problems: above 50 points

Participants work through 3 test blocks that last 3 minutes each. At the end of each block, participants get performance feedback.

What it Measures

The Trier Mental Challenge Test (TMCT) is a computerized tool to induce a high cortisol stress response

Psychological domains

• Working Memory & Attention: Required to solve complex, multi-step mental arithmetic under extreme time pressure.
• Decision-Making: The need to submit answers while managing the distraction of negative feedback.
• Stress: psychological and physiological responses in a challenging situation

Main Performance Metrics

• Total Points: the number of total points earned across the three blocks

Psychiatric Conditions

The TMCT is being used to look at stress responses in the following patient groups (amongst others):

• Major Depressive Disorder (MDD)
• Post-Traumatic Stress Disorder (PTSD)
• Schizophrenia
• Anxiety Disorders
• Alcohol Use Disorder (AUD)

References

Search Google Scholar for peer-reviewed, published research using the Inquisit Trier Mental Challenge Test (TMCT).

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Kirschbaum, C. (1991). Cortisolmessung im Speichel - eine Methode der biologischen Psychologie. Bern [u.a.]: Huber.

Kirschbaum, C., Pirke, K., & Hellhammer, D. (1993). The ‘Trier Social Stress Test’ – A Tool for Investigating Psychobiological Stress Responses in a Laboratory Setting. Neuropsychobiology, 28(1–2), 76-81.

Pruessner, Hellhammer, & Kirschbaum. (1999). Low self-esteem, induced failure and the adrenocortical stress response. Personality and Individual Differences, 27(3), 477-489.