Environmental Sound, Sonic Art, Physical Computing, Performance
Excitations is the collective title for a series of performances and participatory research that explore the experience of listening to the physiological processes of one's own body. The work makes use of biofeedback sensors, which measure data such as blood flow and stress levels. The data is used to create sounds in realtime.
On a superficial level, Excitations seems to simply extend the presence of a performer by means of technology. However, since this technology accesses bodily functions that are difficult to control, longer-term play starts to reveal continuous changes in the subtle physiological processes of the performer's body. Even excitations - impulses beyond conscious control - can become audible.
A performer could apply mental projection, breathing or other techniques to control body reactions and influence the sensor readings in order to create particular sound patterns. However once mental and physical exhaustion sets in, emotional impulses - sudden thoughts, memories or external distractions - usually enter the mind, causing involuntary reactions which also become audible.
So while it is possible to make music with the sounds or to communicate one's mental state to others, it is the unavoidable loss of control that makes for the most interesting listening experience.
In Excitations, the physiological changes taking place in the performer's body are communicated via data sonification. The main data sources are skin conductivity, heart beat and pulse rate of the performer; using non-invasive finger sensors to capture this data.
After designing a wearable sensor interface, a mapping scheme was devised that would translate the incoming data into sound frequencies and eventually musical notes. This process was repeatedly tested in practice, which gradually revealed which mapping strategies were more successful at communicating the nature of the physiological processes to listeners.
The performative aspects of Excitations also evolved iteratively through workshops and participatory action research. Participant observations often led to insightful conversations and suggestions that helped to shape the performative material.
For example, there can be a short time lag between a mental impulse and the way it manifests itself in the body. This delayed reaction usually only becomes noticeable to the person whose body experiences it, but in Excitations, due to the realtime sonification, it also becomes noticeable to others. To allow non-players to synchronise what they observe and hear, slow movements and stillness seem to work best from a performance point of view.
Overall, listening to sonified biofeedback over time can make the characteristics of physiological processes more and more perceptible, especially when the sounds still carry some of the original rhythms and patterns.
Fresh! Festival (May 2005) In the foreground a direct sonification of the performer's pulse that was achieved by making use of pitch. Her galvanic skin response is sonified as quavers in the background. Occasional changes to her stress levels trigger percussion-like instruments (short metallic sounds towards the end).
Time, Flesh and Nerve event (July 2006) A change to the way the pulse has been sonified: a move towards tickering and flicking sounds, as well as using delays and reverb. Again, the galvanic skin response is sonified as quavers in the background.
Florida Electro-Acoustic Music Festival (April 2008) Quite a clear heart beat sound, which is occasionally interspersed with bursts of excitations (irregular high-pitched or burping sounds). About halfway through, changes to the performer's stress levels are communicated via bell-like sounds.
Excitations (2009) An example that sonifies only the stress levels, again using bell-like sounds and extended quavers. Lower pitch gong-like sounds (about 2/3rds through) communicate larger changes occurring to stress levels of the performer.
Excitations was the core component of Michaela Palmer's practice-based PhD, 'Listening to the mind at play - sonified biofeedback as generative art practice and theory', London Metropolitan University, 2010.
Excitations has been in development from 2005 - 2009. The work was performed at the Fresh! Festival (South Hill Park Arts Centre, UK 2005), PARIP 2005 International Conference (Leeds, UK 2005), East End Collaborations (London, UK 2005), e-Performance and Plug-ins conference (Sydney, AUS 2005), Time, Flesh and Nerve event (Lounge Gallery, London, UK 2006), Florida Electro-Acoustic Music Festival (Gainesville, FL 2008) and the DigiCult event (Bristol, UK 2011).
Related publications: Reiser, M (2010) "Listening to the body's excitations", in 'Performance Research', Volume 15, No. 3 (Sept 2010)
Reiser, M (2006) "Learning to play the instrument: how to encourage improvisation in interactive environments", peer-reviewed conference paper, Mindplay conference, London