This year's Charles Darwin Award Lecture for Agricultural, Biological and Medical Sciences at the British Science Festival was awarded to cognitive neuroscientist, Carolyn McGettigan. Here Alan Barker gives us an insight into the event and the fascinating science behind 'The Voice'.
Think about all the ways we use our voices. Carolyn McGettigan spends a lot of time doing just that. Fittingly, Dr McGettgan has a passion for communication: she’s published no fewer than thirty peer-reviewed papers; and when she posted an MRI movie of someone lipsynching to the Adele song “Hello” late in 2015, on YouTube, it went viral. On Tuesday, in the Charles Darwin Award Lecture for agricultural, biological and medical sciences, Carolyn shared with us some of her most recent discoveries.
We started with a rapid tour of human vocal machinery. The sound is sourced in the larynx, two folds of tissue that produce a buzz exactly like the whistle of the blade of grass between your thumbs that I could never master. Above the larynx, the tongue, soft palate and lips provide various kinds of filters to shape that basic vibration into the exquisitely subtle sounds of language, laughter, and song.
How does the brain coordinate all this intricate machinery? Two nineteenth-century physicians discovered parts of the brain – now named after them, as Broca’s area and Wernicke’s area – that control how we produce vocal sounds, and how we perceive them, respectively. But their discoveries depended on physical dissection of damaged brains after death; until now, we haven’t been able to see what’s going on in real time. Now, for the first time, McGettigan and her colleagues are using fMRI scans to help connect mouth movements to the brain regions controlling them.
It’s the relationship between production and perception that matters. We use our voice to project not just the words we speak, but a host of other information about ourselves: how we’re feeling, how we want to be viewed, the context of our ideas, and even our sense of identity. And as perceivers, our brains pick up this paralinguistic information with great sensitivity. It’s a dynamic, social process. But, because that pattern-matching is intuitive, it can sometimes go wrong: stroke victims who lose the ability to speak clearly, for example, are often thought to have taken on a foreign accent – a mismatch that’s so common that it’s now known as foreign accent syndrome.
McGettigan’s work on laughter demonstrates that we process meaning and melody in different parts of the brain. We respond to an authentic laugh with the same parts of the brain that respond to the melody of the voice (parts that, she suggests, “are under the control of an older system”); in contrast, we respond to an artificial or acted laugh with parts of the brain – perhaps more recently evolved – associated with theory of mind (we’re presumably trying to work out what the false laugh might mean).
Carolyn’s more recent research demonstrates further the intricate interconnections between vocal production and perception. Take impersonation: “When people were producing speech to sound like someone else,” she explained, “they were activating the regions of the brain that they might be using to perceive somebody else.” Her work on how the brain controls the vocal tract in language learning could offer insights to help improve speech therapy for stroke patients.
But the real showstoppers were the fMRI images. To see the extraordinary dance of Reep One’s tongue and lips as he beat-boxed, and to hear Jenny Ruth Adams singing live while watching her own vocal tract on screen, was to witness with vivid immediacy the flexibility and subtlety of the human voice – a pattern of neural control and muscular coordination that is surely unique in nature.
Alan Barker, British Science Festival Swansea, September 2016. Alan Barker is a writer and training consultant specialising in communication skills. He is Managing Director of Kairos Training Limited.