Quorum Sensing : An Interactive Installation

As biologists make cultures of living matter in Petri dishes, I make cultures of biospheres within a computer with my artificial-life programs.

Using genetic algorithms, I create autonomous virtual creatures, which are simultaneously organic and artistic. A substrate, generated by a cellular automata algorithm, nourishes them. When they die, their bodies decompose themselves into small particles similar to virtual oligo-elements that carry the regenerative force of this living environment. These interdependent life cycles generate a complex, evolving system in perpetual symbiosis that forms a virtual biosphere.

Through the interactive installation Quorum Sensing, my biosphere cultures become incorporated into reality, and visitors can make contact with them (Fig. 1). The installation is located in a room with a video projector on the ceiling. A carpet containing sensors enables the computer to determine the position of the visitors. Beneath the visitors' footsteps, an image draws itself on the ground. Within this effervescence of light, shapes like microorganisms suddenly appear. These are the virtual creatures.

When a single visitor enters the space, virtual creatures immediately jump forward to greet her and attach themselves to her steps. If another visitor enters, a beam interconnects the two people. Attached in spite of themselves, they find intimacy transgressed. But this strange beam of light never unveils the mystery of its nature until the arrival of a third visitor. Then an "emergence" occurs: the biosphere appears, but this trio will never be able to see it in its totality. A second "emergence" shoots out as soon as a fourth visitor enters the installation. According to the number and relative location of the participants, configurations on the ground become increasingly complex, giving rise to a lace-like fugitive form of momentary life span, revealing, to a selected few, details of the biosphere, while to others it remains invisible.

Fig. 1.

Chu-Yin Chen, Quorum Sensing, interactive installation at the @rt Outsiders Festival, Paris, 2002. When there are three visitors in this installation, this biosphere appears as a substrate flowing on the ground in which artificial life proliferates.

© Chu-Yin Chen

When another person enters the scene of the installation, the projected picture advances towards him to welcome him into the community of visitors. If somebody leaves, the pictures instantly withdraw towards the remaining community. When visitors stand motionless, contemplating the virtual world, the figure transforms itself into an image reminiscent of an amoebic polymorphism that flows and retracts naturally under the feet of the visitors.

The work also includes a sound landscape that reflects the feeling of this space, with its ebb and flow related to the virtual creatures' life cycles. Strange noises and cries of animals are emitted when visitors approach. A set of visitors generates a polyphony that penetrates, like an undertow, the calm of the place.

This installation highlights a new mode of collective interaction based on the behavior of the visitors, both among them and towards the virtual world. Through their mutual comprehension and cooperation, they create an intra- and inter-communication. An identical phenomenon, called "quorum sensing," is observed among bacteria. The term is used to describe a communication mechanism that activates group behavior.

Quorum Sensing explores the collective consciousness of visitors and their behavior. If virtual creatures return, if artificial life proliferates around visitors, it is due to the emergence of the collective interactions of the quorum sensing!