Psychological stress is an ubiquitous challenge across human cultures affecting mental and physical health. Recent evidence indicates that performance tasks combining elements of socio-evaluative threat and uncontrollability elicit reliable stress responses. The Trier Social Stress Test (TSST) is the most frequently used psychological protocol in stress research; however, to date it has only been available in a single-subject version. In particular, there is an increasing need in several emerging research fields such as stress research or social neurosciences for a standardized research tool to expose relatively large groups of subjects to controlled simultaneous stress. In search of a laboratory stressor that allows simultaneous stress exposure in a group format, we exposed a total of 25 healthy male participants to the Trier Social Stress Test for Groups (TSST-G; public speaking and mental arithmetic tasks in front of a panel of two evaluators in groups of six participants) and a specific control condition. Results showed that the TSST-G induced significant increases in cortisol, heart rate, and psychological stress responses. The TSST-G provides a novel, effective, and economical protocol for experimental paradigms requiring simultaneous stress induction in multiple participants.
Human beings are fundamentally and pervasively motivated to form and maintain enduring positive interpersonal interactions (Baumeister and Leary, 1995). Depending on the circumstances, social interactions can be a source of stress, contributing to a wide spectrum of somatic, psychosomatic, and psychiatric disorders with major public health significance, or buffer against stress (Ruberman et al., 1984, House et al., 1988, Kirschbaum et al., 1995, Uchino et al., 1996 and Heinrichs et al., 2003).
There is substantial evidence indicating that exposure to psychosocial stress alters hypothalamic-pituitary-adrenal (HPA) axis function, which regulates the release of cortisol, an important hormone associated with psychological and physical health functioning (Chrousos, 2009). More specifically, a recent meta-analysis showed that motivated performance tasks combining elements of socio-evaluative threat and uncontrollability elicit robust and reliable psychological and biological stress responses (Dickerson and Kemeny, 2004). Socio-evaluative stress occurs when an aspect of the self could be negatively judged by others (Gruenewald et al., 2004). Uncontrollability refers to the inability of the individual to affect an outcome by a behavioral response (Thompson, 1981).
The Trier Social Stress Test (TSST; Kirschbaum et al., 1993) was developed for the induction of moderate psychosocial stress in a laboratory setting. As this stress paradigm combines uncontrollable and socio-evaluative elements in a highly standardized manner, it reliably leads to psychobiological stress responses (Dickerson and Kemeny, 2004), including 2–3-fold increases in HPA axis and cardiovascular stress responses. Due to large effect sizes and high reliability, the TSST has become a worldwide standard for psychological stress induction under controlled conditions. In brief, the original TSST protocol consists of a 5-min public speaking task (mock job interview) and a subsequent 5-min mental arithmetic task (serial subtraction) performed out loud in front of a panel of two unfamiliar evaluators and a conspicuous video camera. In addition to being used in studies on the deleterious effects of stress, the TSST has also been used as an experimental paradigm to investigate different stress buffering effects (e.g., social support, social attachment, physical contact, exercise, breast-feeding) (Heinrichs et al., 2001, Heinrichs et al., 2003, Ditzen et al., 2007, Ditzen et al., 2008, Rimmele et al., 2007, Rimmele et al., 2009, Simeon et al., 2007, Storch et al., 2007 and Robles et al., 2009). As the TSST is a single-subject method, the paradigm is unfortunately not applicable to experimental studies that require group testing, such as numerous study designs in social psychology, social neurosciences or behavioral economics. For economical experimental testing of relatively large groups of individuals and to avoid excessive expenses and infrastructures, a controlled simultaneous stress protocol for multiple individuals is required.
To date, there have been no experimental studies that directly address the development of a simultaneous group version of a psychosocial laboratory stressor in a randomized controlled study design. As a consequence, we undertook a controlled trial to develop and evaluate a new tool for standardized social stress exposure in a group format, which we hypothesized would significantly increase cortisol, heart rate, and subjective ratings. In addition, no or little changes of biological and psychological parameters were hypothesized in response to a specifically designed control condition containing all factors of the stress condition except for the psychosocially stressful components (i.e., socio-evaluative threat and uncontrollability).
