Collective appetite

How the social environment influences group eating

Have you ever wondered why the last piece of cake is left untouched when we eat together in Germany? Because no one dares to touch it. Maybe you have heard: “It is a matter of good manners” – or in German: “Das ist für den Anstand.” Beyond that, there is a myriad of other eating behaviours. Perhaps they will now be decoded by psychologists Britta Renner, Harald Schupp and Jana Straßheim, together with the team behind the project Individual and collective appetite – how is eating shaped by social influence?

The aim of this project is to determine how social context influences the eating behaviours of human collectives. “In our studies, we analyze behaviours, including kinesics, as well as proxemics, to explore whether there are fine-scale processes of behavioural synchronization or anti-synchronization within a group while eating,” says doctoral student Jana Straßheim.

Perceived synchrony is assessed on individual and group level and through external raters. But the researchers want to take it a step further. “In addition, we want to use automated coding to analyze synchronization and perceived synchrony in greater depth,” outlines Britta Renner. To automate this data analysis, the team is collaborating with the project Human-in-the-loop analysis by Daniel Keim and Matthias Kraus. “The innovation in our project lies above all in the fact that behavioural observation studies in groups of humans are very rare,” says Renner.

The team developed a new paradigm for the project, where they study groups of three participants while experimentally varying food presentation and the valence of the group context. Food manipulation involves snacks that are served on a separate plate for each individual (individual task) or on a shared plate from which the participants can snack (joint task). First results suggest that eating from a shared plate increases perceived synchronization as compared to eating from a separate plate.

Laboratory Setup

“Conducting studies with groups has been the greatest challenge due to the changing governmental regulations since the start of the pandemic,” says Straßheim. They also set up a new, mixed-reality commensality design using a videoconferencing system. In this setting, ready meals are delivered to the three participants’ homes, and they are asked to eat with their digitally present lunch companions.

The team is working together with three newly funded CASCB projects to add new analysis, such as eye movement. This enables the researchers to look at gaze movement and duration, thus recording attention and eye focus of individuals during a conversation and while eating together. Gaze movement, together with their current measurements of synchronization, helps the researchers to further investigate the underlying processes in collectives.