Investigations of how the human brain processes music and the potential health benefits of music listening have predominantly focused on controlled experimentation that takes place in the lab. This is necessary because of at least two reasons:
1) To be sure that it is music itself, and not something else that is producing the observed effects, it is necessary to carry out experiments where the music, the amount of listening, the conditions of listening and the physiological reactions are carefully controlled and monitored, and the effects of confounding factors are minimized.
2) Studying how the brain processes musical features usually requires the use of imaging equipment that is expensive and can’t really be carried around, and the experimental paradigms include repeated presentation of sounds to improve the signal-to-noise ratio (the brain responses that are being measured are very weak and can get “lost” in the background noise of the brain).
At the same time, researchers recognize the limitations of controlled experiments within lab settings. One of the most important ones is that studies conducted in the lab are sometimes very far removed from real life and their results might not be generalizable to everyday situations. The importance of creating experiments with more natural stimuli, and conducting studies in settings that resemble real life comes up frequently in scientific discussion.
The rapid development and expanding accessibility of new sensor technology offer intriguing possibilities for out-of-the-lab experimentation. Even though we are very far from having personal MRI machines or from great numbers of individuals wearing high-quality EEG bands throughout the day, measurement of physiology outside the lab has become a lot easier.
For instance, the sensors in regular smartphones and popular health bracelets and rings currently allow tracking of multiple interesting indicators with relatively good quality, such as heart rate and heart-rate variability, skin conductance, and movement. This kind of data can be used to investigate several interesting and important questions related to music in real-life listening situations. For example, with the help of heart rate and skin conductance data, we could look at the immediate emotional responses to music such as relaxation or arousal, or the effects of music listening on management of mood disorders. With the help of movement-related data, we could investigate the effects of music listening on decreasing sedentary activity, or on improving gait in Parkinson’s patients in real-life settings. Perhaps the greatest advantages from scientific investigation in real-life settings with the help of new sensor technology will first be gained in fields where monitoring of an individual’s activity during daily life is particularly important.
As the quality of mobile EEG-headsets improves, and they achieve greater adoption among music listeners, there are exciting new possibilities for the investigation of the how the brain processes music and sound. Typically, EEG studies on auditory processing require repeated presentation of sounds. This is done to record what are called ‘evoked responses’ – the electrical activity of the brain generated in precise response to the sound presented. In order to record good-quality evoked responses, each sound is presented hundreds of times. This results in experimental paradigms that very often do not resemble real music. But what if, instead of presenting the same sound repeatedly to a single individual, the sound would be presented only once, but to millions of people? This would probably result in as good a signal-to-noise ratio for the response as with traditional measurement, but without the unnatural repetition of the sound, and in a much more pleasant research setting for the subject!
Another interesting question that could be investigated with large-scale EEG measurement is how music can synchronize individuals. Previous research has shown that oscillatory brain activity becomes synchronized between individuals during both musical and non-musical interaction. Investigating this inter-brain synchronization in concert settings, among the performers and members of the audience, as well as between the performers and the audience could further our understanding of this beautiful phenomenon and its significance for musical performance and enjoyment.
These are just a few examples of the possibilities that commercial sensor technology could offer to scientific experimentation. Obviously, there are some challenges associated with the data acquired from such measurements, pertaining mostly to the quality of the data, and the need to control confounding variables that abound in varied listening contexts in order to tease apart exactly what is causing the observed effects in individuals. We don’t yet know whether there are problems in this kind of data acquisition that cannot be overcome. But with the wonderful possibilities for new discovery that are emerging with advances in sensor technology, we at the Sync Project think it’s high time to find out.
written by Marko ahtisaari
Dumas, G., Nadel, J., Soussignan, R., Martinerie, J., & Garnero, L. (2010). Inter-Brain Synchronization during Social Interaction. PLoS ONE, 5(8), e12166. doi:10.1371/journal.pone.0012166
Lindenberger, U., Li, S.-C., Gruber, W., & Müller, V. (2009). Brains swinging in concert: cortical phase synchronization while playing guitar. BMC Neurosci, 10(1), 22. doi:10.1186/1471-2202-10-22