Dr Harry Witchel explains how entrainment can offer science a new way to study the power of music.
Hearing is the Cinderella sense: always working, under-appreciated and often overlooked. Try watching a movie (especially something emotive like a cartoon) with the sound off – it will be eerily unemotional. Now “watch” the same movie with the sound on but with your eyes closed. Although usually it will be impossible to understand completely (or even to know whether each event is positive or negative), the soundtrack alone will be arousing and powerful.
We may be missing an opportunity to tap into music’s power. Music has been used for at least the past two millennia as an intervention in medicine – to soothe and calm, and for pain relief. Yet, now music is mostly relegated to the sidelines. In hospitals and schools, music is not integrated with everything, but is incorporated as a fat-free gratification, rather than as a fundamental endeavour. Many medical journal articles even referred to music as little more than a “distractive audio stimulus” [von Leupold et al 2007; Thornby et al., 1995]; this is obviously an over-simplification, as even these scientific studies showed that music – with its rhythms, repetitions and melodies – is an exceptional sound with remarkable qualities. For example, in 2015 a meta-analysis (research that amalgamates all the other research studies) showed that listening to music improves post-operative recovery of surgical patients [Hole et al., 2015].
Scientists have much evidence showing music is potent. Music has the power to heal the sick, to make runners faster, to make children smarter, and to transform a crowd into a gathering [Terry et al., 2012; Forde-Thompson et al., 2001]. How?
The new scientific breakthroughs that are driving forward the science of music means that we are beginning to understand how music works its magic. If you want to convince a sceptical scientist that music causes many positive effects, statistics are not enough – you need evidence for a mechanism showing how one thing causes another. The major breakthrough in our understanding of music, and how it is a no ordinary sound, involves the growing body of evidence on how music causes entrainment. Entrainment is when one thing – such as a person or a body — synchronises to another, such as music. Examples of entrainment include foot tapping to music, dancing to music, and two people shaking hands.
Not only does music make us want to entrain to it by dancing to its rhythm. Scientists have shown that our brain waves entrain to the rhythm of music [Doelling & Poeppel, 2015]. This breakthrough is based on the technology magnetoencephalography, which works as follows. Tiny magnetic fields are naturally generated by the activity of individual brain cells just underneath the skull, and magnetic fields can be detected by placing sensors on the head. The clashing activity of individual nerve cells would be far too small to detect from the din of the background brain activity, but when large numbers of adjacent neurons are synchronised to each other (or are all synchronised to the same external event, such as music), the combined magnetic field is large enough to be detected outside the skull.
The scientists from New York University showed that both nonmusicians’ and musicians’ brain activity became synchronised to the pulse of the music when the piece had more than one note per second. But when the music’s pulse was slower than that, only the musicians’ brains synchronised in this way. This shows that how we attend to music cognitively affects us at the most basic brain level – the frequency of cellular activity – and that these affects are in part mediated by the musical expertise of the listener.
This study, and others that are similar, are providing us with tantalising glimpses as to how music can affect us emotionally via its direct effects on entraining cells of the brain.