A scalable and robust system for Audience EEG recordings

The neural mechanisms that unfold when humans form a large group defined by an overarching context, such as audiences in theater or sports, are largely unknown and unexplored. This is mainly due to the lack of availability of a scalable system that can record the brain activity from a significantly large portion of such an audience simultaneously. Although the technology for such a system has been readily available for a long time, the high cost as well as the large overhead in human resources and logistic planning have prohibited the development of such a system. However, during the recent years reduction in technology costs and size have led to the emergence of low-cost, consumer-oriented EEG systems, developed primarily for recreational use. Here by combining such a low-cost EEG system with other off-the-shelve hardware and tailor-made software, we develop in the lab and test in a cinema such a scalable EEG hyper-scanning system. The system has a robust and stable performance and achieves accurate unambiguous alignment of the recorded data of the different EEG headsets. These characteristics combined with small preparation time and low-cost make it an ideal candidate for recording large portions of audiences. Highlights A scalable EEG hyper-scanning system for recording audiences and large groups is presented with the following characteristics. Off-the-shelve, low cost components, namely a MUSE EEG headset, a Raspberry Pi computer and Photodiode. A Python library, available to the public, has been specifically developed from first principles, optimized for facilitating robust recording over Bluetooth even when multiple EEG headsets are in close proximity. The use of photodiodes provides unambiguous data alignment between the different systems. A proof-of-concept system with 10 EEG headsets has been tested in the lab but also in naturalistic conditions, recording members of the audience in four different long movie screenings in the cinema of the German Film Museum.