How do we define rhythm in science?
We spoke to Philosophical Transactions B guest editor, Dr Rachel Smith, whose recent theme issue ‘Communicative rhythms in brain and behaviour’ brought together multiple disciplines to explore a range of questions relating to rhythmic communication, to find our more.
What is rhythm?
Rhythm is patterning in time. Often, this means regularly repeating patterns, but not always. Some of the most exciting rhythms in music and language are found when the pattern departs from regularity.
Does the definition of rhythm differ across disciplines?
Rhythm means very different things to different people. Partly this has to do with timescale – in nature one can find patterns that repeat at intervals ranging from milliseconds to millions of years, so it’s not surprising that, say, a neuroscientist looking at EEG should have a different take on rhythm compared to a geologist. Even within disciplines that focus on human behaviour, like linguistics and music, there are hugely divergent opinions as to how we should define and analyse rhythm.
What are the major themes of this special issue?
Our focus is rhythm on a human scale. We look at how rhythm helps individuals to make sense of their environment, such as the interaction between music-makers and their audiences, conversational partners, babies and their caregivers. Another theme is what speech and music have in common rhythmically, and how they differ. Finally, several articles focus on what can go wrong, whether in the simple form of being unable to move in time to a beat, or in cases of brain injury.
What are examples of rhythmic behaviours?
Walking; making music; tapping to the beat; speaking; bouncing a baby; co-ordinating one’s breathing when taking turns to speak in a conversation. These are just a few of the behaviours mentioned in the theme issue – there are dozens more.
How is rhythm linked to cognition?
Rhythm seems to facilitate many aspects of cognition. It’s part of the scaffolding that people use to predict events in the environment, to structure their behaviour in time, and to share and coordinate their experience.
How is rhythm involved in speech and language?
The rhythm of speech has been notoriously hard to define. In fact, some researchers think speech is anti-rhythmic because most efforts to find regularity in it have failed. It’s true that we rarely want to get up and groove to the sound of someone talking. But some powerful speech forms, like chanting and certain types of oratory, are experienced as highly rhythmic. And disrupting the timing of events even in ordinary forms of speech makes it much harder to understand.
Why is it important to study rhythms in brain and behaviour?
If rhythm supports cognition there must be a biological basis for this, so it’s natural to investigate the aspects of neural processing that are involved. But studying the actual rhythmic behaviours themselves – which are often highly complex – is important to ensure that theories are developing in sensible directions.
How is the field likely to develop in the future?
I think that the focus will increasingly be on rhythm in natural contexts, especially involving joint action. Technologies have developed to allow sophisticated recordings of behaviour that are not too intrusive, and methods for studying two interacting brains are also beginning to develop.
What made you pursue a career in speech, language and linguistics?
Speaking is a very complicated business, easy as it seems. Understanding it requires contributions from many disciplines in the biological and physical sciences as well as the arts, and there are applications from technology through to therapy. My own area of interest is phonetics – the linguistic patterning of sounds – but I like working in a field that is very diverse.
Interested in guest editing an issue of Philosophical Transactions B? See here for more information.