"Minus×Minus=Plus" is an interactive EEG installation that makes stress visible and shareable.
Through real-time visuals and haptic interactions, participants explore new ways of expressing, connecting, and relieving stress together. I worked on this project in the Future Spaces Vision Lab, led by Prof. Mirna Zordan.
Project Overview
Sharing stress helps people cope with cognitive and emotional burdens by connecting with others. However, most biofeedback systems for stress management focus on individuals, limiting opportunities for relational sensemaking and social interaction. Moreover, touch has been underexplored in social biofeedback, despite its potential for embodied forms of stress sharing. We present “Minus×Minus=Plus”, an interactive installation that externalizes collective neural activity to create a shared affective space. The system allows two participants to visualize their stress in real time through EEG and to transform it together through two haptic interactions, including object-mediated interaction and direct interpersonal touch. Exhibited in the Sea World Culture and Arts center (SWCAC), The installation was tested with 110 participants (55 pairs). Results show that the system facilitated stress sharing process, especially by increasing participants’ willingness to express. Our analysis also provides insights toward an initial quantitative measure of mediated stress sharing and highlights the roles of visual and haptic modalities in cultivating shared affective experiences.
System Design
The system consists of a large projection screen and two stands, each equipped with a touch ball and a TGMA EEG headset. Participants stand side by side, facing the projection, with their stress signals continuously captured and visualized. The entire experience lasts approximately six minutes and is structured into three stages of about two minutes each.
Installation Layout
Different Stages of Visual Feedback
● Visualization Stage: Once participants have correctly worn their EEG headsets and activated the touch balls, their stress signals are projected as two cube clusters, each rendered in a distinct color corresponding to one participant. The clusters appear side by side, aligned with the participants’ positions, so that each individual can clearly recognize which visualization is their own. Small cubes dynamically assemble into larger structures, with the number of cubes varying in real time according to the detected stress index. Higher stress values produce denser clusters.
● Merging Stage: Participants will press their touch balls simultaneously. This action causes the cube clusters to move toward the center of the screen, with speed proportional to the applied force of each participant. If one person stops pressing, the clusters return to their original positions. Successful sustained pressure by both participants enables the clusters to meet and intertwine, producing a dynamic fusion of their stress visualizations. This stage emphasizes synchronized collaboration and mutual effort.
● Explosion Stage: In the final stage, participants maintain single-hand pressure on their own touch ball while holding each other’s free hand. This interpersonal touch triggers the merged clusters to condense into a shared sphere, which then bursts outward. The intensity of the explosion reflects the applied force on the balls, and sustained handholding causes the sphere to explode completely and disappear, symbolizing the release of shared stress.
● Merging Stage: Participants will press their touch balls simultaneously. This action causes the cube clusters to move toward the center of the screen, with speed proportional to the applied force of each participant. If one person stops pressing, the clusters return to their original positions. Successful sustained pressure by both participants enables the clusters to meet and intertwine, producing a dynamic fusion of their stress visualizations. This stage emphasizes synchronized collaboration and mutual effort.
● Explosion Stage: In the final stage, participants maintain single-hand pressure on their own touch ball while holding each other’s free hand. This interpersonal touch triggers the merged clusters to condense into a shared sphere, which then bursts outward. The intensity of the explosion reflects the applied force on the balls, and sustained handholding causes the sphere to explode completely and disappear, symbolizing the release of shared stress.
The below figure shows the process of data detection and visualization. EEG headsets and touch balls provided real-time signals that were processed and mapped in TouchDesigner. A C# program calculate a stress index from the ratio of Beta to Alpha bands in EEG data and transmitted it to control cube density. At the same time, Arduino capture ball pressure and detect interpersonal touch through circuit continuity, which modulated cube movements.
System Hardware, Data Flow, and Visualization Mapping
