The Trier Social Stress Test (TSST) is a standardized laboratory procedure widely used in human research. Developed in 1993 by Clemens Kirschbaum and colleagues at the University of Trier, its purpose is to reliably induce acute psychological stress under controlled experimental conditions. This method allows scientists to investigate the body’s responses to acute psychosocial stressors. It addresses limitations of earlier stress induction methods by producing larger and more reliable physiological effects.
Understanding the Trier Social Stress Test
The TSST is designed to elicit a physiological and psychological stress response by combining elements that provoke stress: public speaking and mental arithmetic, performed in front of an unresponsive audience. The rationale involves two psychological components: social evaluative threat and uncontrollability. Participants anticipate being judged negatively during their performance, which creates a social evaluative threat.
Uncontrollability stems from the difficulty of the tasks and the lack of positive feedback or encouragement from the audience. This combination aims to create a situation where individuals feel their performance is under scrutiny and have limited control over the outcome, maximizing stress induction. The design exploits human vulnerability to socially evaluative situations, leading to consistent activation of stress systems.
Administering the Test
The administration of the TSST follows a standardized procedure to ensure consistent stress induction. Participants are given about 10 minutes to mentally prepare a five-minute speech, often describing why they would be a good candidate for their ideal job. They are informed that their speech will be videotaped and reviewed by a panel of judges trained in public speaking, enhancing the social evaluative threat.
Following speech preparation, the participant delivers their speech in front of two or three stern-faced evaluators who remain unresponsive and maintain eye contact, intensifying the social evaluative pressure. A video camera or microphone is present to reinforce the feeling of being recorded and evaluated. Immediately after the speech, participants are given a mental arithmetic task, such as serial subtraction (e.g., counting backward from 1022 by 13s). If a mistake is made, they are instructed to start over from the beginning, adding to the feeling of uncontrollability and pressure. This stressor phase, combining speech and arithmetic, lasts around 15 minutes, divided into 5-minute components. Pre- and post-stress rest periods, often 20 minutes, are included for baseline measurements and to observe recovery.
Measuring the Stress Response
To assess stress induction and study its effects, various physiological and psychological parameters are measured during and after the TSST. A primary physiological measure is salivary cortisol, which serves as an indicator of hypothalamic-pituitary-adrenal (HPA) axis activity. Saliva samples are collected at various time points, such as before the test, immediately after the stressor, and at regular intervals during recovery (e.g., 10, 20, 30, 45, 60, and 90 minutes post-task). Cortisol levels typically peak in saliva approximately 10-30 minutes after the stressor begins.
Cardiovascular responses are also frequently monitored, including heart rate and blood pressure, which reflect sympathetic nervous system activity. These measures are often taken continuously or at regular intervals throughout the test and recovery phases. For psychological assessment, self-report questionnaires gauge subjective stress, anxiety, and mood. Common tools include Visual Analog Scales (VAS) to rate current stress levels, and the State-Trait Anxiety Inventory (STAI) to measure state anxiety immediately following the stressor. These combined measurements provide a comprehensive picture of the individual’s stress response to the TSST.
Research Applications and Findings
The TSST is a tool in scientific research, offering insights into individual differences in stress reactivity. It helps researchers explore how various interventions, such as mindfulness or social support, might modulate physiological and psychological responses to stress. The test is also used to investigate neurobiological mechanisms underlying stress responses, including HPA axis and sympathetic nervous system activation.
Researchers frequently apply the TSST in studies involving populations with conditions like anxiety disorders, depression, and post-traumatic stress disorder (PTSD), as well as in psychoneuroimmunology research to understand the interplay between stress and the immune system. TSST research consistently shows it reliably induces cortisol responses and increases heart rate and subjective anxiety in most participants. This consistent induction of stress allows for controlled examination of stress-related phenomena in diverse research contexts.