In the second of this 2-part interview commentary on the research project Bicameral Music, Vaughan Macefield talks with InteraXon about his interest in performance, dance, and studying the nervous system.
In October 2012, Erin Gee announced a collaboration with neurophysiologist Vaughan Macefield (Australia) and roboticist Dr. Damith Herath (MARCS Institute) called ‘Bicameral Music’. Bicameral Music is a performance that Gee describes as combining robotics, technology and raw emotion. The team has been researching and mapping raw emotion, translating electric currents in the brain into a decipherable auditory experience. The end goal of their research is a symphony, performed live in Montreal, in 2013
Your recent research and collaboration focuses on music created by raw emotions, derived from electrical currents in the human brain. What is the inspiration behind this project?
As a neurophysiologist, I am interested in how the nervous system encodes various aspects of its environment via specialized sensory organs – with a particular interest in touch and proprioception (our ability to know the positions of our limbs in space, which is critically important in dance) – and how the sympathetic nervous system controls flow through blood vessels and controls sweat release. Given that blood flow through the skin decreases when we are aroused, excited, anxious or afraid, and we start to sweat in each of these states, ever since I have been recording these sympathetic nerve signals I have always been fascinated by how they provide a very precise measure of the emotional state of a person. Indeed, by tapping into the spontaneous or evoked bursts of skin sympathetic nerve activity (SSNA) – by inserting fine needles (microelectrodes) into a peripheral nerve – one can determine what “turns a person on” by asking them personal questions or showing them specific images.
My colleague, Assoc Prof Luke Henderson (University of Sydney), and I have recently been scanning the brain while recording these nerve signals, in order to identify how these signals are generated when a person is emotionally engaged. But the real inspiration for this project goes back to the mid-80’s, when I saw Montreal-based dance outfit La La La Human Steps perform in Sydney. I am a fan of modern dance, but I still remember this show very well. They had attached a cardiac microphone onto the chest of a member of the audience and connected it to a loudspeaker. As the dancers performed, the heartbeat became faster and faster, the dancers’ tempo accelerating accordingly. So, here we had a performance that was influenced by a member of the audience. That person happened to be me, and this snippet of experience has been in my memory all this time, and did not really surface until I met Erin when she performed with Stelarc and a robot in Sydney last year. I was watching this tall, beautiful woman with her amazing presence and it got me thinking: she would be great to talk to about this potential project, which had been on a very slow bake for about three years. So, I went up to Erin after her performance, complimented her and said a few corny things like, “Hey, do you like Laurie Anderson?” I suggested that she would be ideal to work with on a project I had in mind and we arranged to meet up for coffee the next day in inner-city Redfern. So, this would not have developed without Erin and her artistic and musical talents, and it has been a very fruitful collaboration thus far.
How do we ‘perform’ emotion?
Yeah, it’s true – everyone “performs emotion” differently, though their physiological effectors are the same. Everyone can break out into a cold sweat (so called because the blood vessels in the skin constrict and sweat is released), and may develop goosebumps (erection of our vestigial hairs). These responses are what also occur when we are trying to control our body temperature: our skin goes white (blood vessels constrict) and we get goosebumps (piloerection) when we are cold, our skin goes red (blood vessels dilate) and we sweat when we are hot. Indeed, this is the primary purpose of the sympathetic innervation of the skin, to control our body temperature, but it has also been commandeered as a means of emotional expression. Some people are more reactive than others; some people blush, and some people develop excessive sweating from the palms or armpits (hyperhidrosis) in embarrassing situations. Others may be able to suppress many of the physiological markers of emotional processing, and it is known that psychopaths have very blunted emotional responses. So, we perform emotion with a key set of players: skin blood flow, sweat release, heart rate and dilation of the pupils. We all know that our pupils dilate when we are aroused, and is known that pupillary diameter of two people emotionally engaged will mirror each other. Our pupils dilate when we are in love: a drug used to be was dropped into the eyes of young women to dilate the pupils and make them more attracitive – this drug was referred to as “belladonna” (beautiful woman).
Music is very mathematical; here you’ve taken a collection of raw neural data and converted it into numbers to create sound, using specialized software. Yet your plans for future performances using this data are very aleatoric. How do the elements of chance, and the logic of math, complement each other in your research?
There certainly are chance elements in the nerve signals I record, but they are governed by both higher-order and lower-order neural processes. Individual neurones are either silent or active. In binary terms they are either in the “0” or “1” state, and I use this to quantify the firing properties of individual neurones. Erin is very interested in this aspect, and has been using the nerve events (spikes) to generate percussive sounds that fit with the on-off nerve events.
How could the electrical signals that are recorded – and the resulting performance – be affected by stimuli like stress, sleep, food, or the ability to focus and concentrate?
Yes, everyone is different, but how they “perform” will be determined both by their “state and trait” – how they “feel” in general, day to day (trait), and how they feel now (state). So, current factors such as stress may well affect how they respond to emotional triggers. This is interesting, as both will influence the performance. A person who always experiences stage fright may well have a very amplified experience in the current context.
Could this research have possible medical applications, or cross-over into other areas of neuroscience?
This is actually very exciting, as I am interested both in the artistic aspects of this work (many scientists are interested in, and some participate in, the arts) and the potential applications. Indeed, given that how we express ourselves emotionally is key to how we are perceived by society, it may be possible to use approaches similar to those we are developing here to “train” the emotional expression of individuals for whom such expressions are difficult. By using non-invasive markers of emotional expression – skin blood flow, sweating, pupil diameter, heart rate and respiration – we may be able to amplify the emotional markers in people with autism spectrum disorder. My conversations with psychiatrist Prof Rhoshel Lenroot (University of New South Wales) indicate that this could be a potentially very fruitful area: a child with difficulty expressing emotions may well learn to interact more fully following training with a robot or avatar that amplifies his or her bodily responses to standard emotional triggers.