A mouse in an elevated plus maze looking out between two walls of the maze. Copyright: Dennis Mink

Stress transmission in groups

Short and long-term spread and modulation of individual psychological stress states in the collectives

When was the last time you felt stressed? Although stress is an everyday and omnipresent phenomenon, there are still many unanswered research questions. One poorly investigated, but very important field is the transmission of stress within the collective. An interdisciplinary research team led by Hanja Brandl, Jens Preussner, and Petra Wirtz is investigating psychological stress transmission across birds, mice, and humans.

Within their project Short and long-term spread and modulation of individual psychological stress states in collectives, the biologists and psychologists observe individuals in groups and try to uncover to what extent our social environment affects our own emotional and psychological condition. They are eager to find out the following: In which physiological systems is stress transmission observable? What are the influencing factors? And what is the role of hormones in transmission across different species?

One very important aspect for the researchers is to set up their experiments in as natural a way as possible. In humans, they observe stress transmission in orchestras as well as psychological synchronization during speed-dating and chess tournaments. To study mice, the researchers have compiled and validated a Live Mouse Tracker system in their laboratory, which they set up with the help of colleagues from France. The method combines computer vision through a depth-sensing infrared camera that can record the posture of mice, machine learning for animal and posture identification, and radio frequency identification (RFID) of mice implanted with an RFID tag.

So far, the main experiments with mice and birds have been successful. “We were the first to establish a standardized paradigm for social stress transmission in mice, allowing us to conduct pioneering research on the effects of stress in different fields, such as physiology, behaviour, and immunology,” says Marcus Goettrup. Due to the COVID-19 restrictions, experiments with humans have been difficult. However, the research team is optimistic about completing the data collection part soon. It is certain that we will have a better understanding in a short while of why we are stressed when part of a group.