"While animals are capable of communicating, they don’t have language." According to Professor Johan Bolhuis, human language is unique due to our creativity. We combine letters and words in endless variations, something animals are unable to do. And yet: certain animals do apply elements of language, which can teach us something about ourselves. "There are some very interesting similarities between the way songbirds learn to sing and the way children learn to talk."
What birdsong has to teach us about how we learn to talk
Professor of Cognitive Neurobiology Johan Bolhuis and his research group are studying how the song of the zebra finch is structured. "Gabriël Beckers, Sita ter Haar and myself are exploring the neurobiological aspects, while our colleague Carien Mol is focusing on the behavioural side." The million-dollar question is: can we distinguish specific aspects in birdsong that also play a role in the way children acquire speech? Prosody would be an example of such an aspect. Bolhuis: "In other words, the emphasis, intonation and rhythm of speech, which allows us to convey all kinds of emotions. Prosody is a vital component of human speech and plays a major role in language acquisition. Children must learn to differentiate within the flow of sounds they hear in order to figure out which part is a word."
The question is therefore whether songbirds apply a similar prosodic structure. Bolhuis: "Every zebra finch learns a song from its father. We presented young birds with their father’s song, but with the elements arranged in a different order. Which didn’t matter, as it turned out – they recognised the song just as easily. We also considered the pauses between the different portions of the song, and what would happen when you prolong those pauses, or remove them entirely. As it turned out, that didn’t seem to make much difference either, although it could be a prosodic cue meaning 'pay attention, a new element starts here'. We want to find out if this is a tool that helps the animal learn the song."
Another study has shown that zebra finch fathers sing differently to their young than they normally do. Bolhuis: "There is a great deal of discussion surrounding the special tone that many human parents use when talking to their babies: does it have any effect? Does it help children learn the language better? And if so – going back to the baby birds, would it help them if their father were to sing more slowly, for example, or pause a bit longer in between parts? That could potentially be the next step in our research – with a continued focus on the parallels between songbirds and humans."
We have more in common with zebra finches than you think
Those parallels exist on a number of levels, Bolhuis explains. "At the behavioural level, there are some interesting commonalities. Birds and people both learn new sounds from adults, and both go through a highly-receptive learning period. I tried to learn Hungarian, for instance, but that’s virtually impossible. It’s an insanely complicated language with some very odd sounds. While my daughter, being a small child, was able to pick it up effortlessly. The same applies to these songbirds. When they’re young, it’s quite easy for them to learn a song; but the older they get, the more difficult it becomes."
Additional parallels exist at a cerebral level. "That’s something you might not expect, since these birds have such tiny little brains. Yet one of the things we’ve discovered here in Utrecht is that the left cerebral hemisphere plays an important role for both songbirds and humans. When we speak or listen, most of the accompanying activity can be observed in specific areas on the left side of the brain. It's much the same in birds. When a bird hears the song it learned from its father, there is a flurry of activity in the left cerebral hemisphere."
According to Bolhuis, the crucial question is: does that mean that songbirds have language in the same way we do? "The answer is the subject of heated debates. We got involved in that debate, together with MIT linguists who were interested in the biology and evolution of language. In the end, we concluded that there is no reason to believe the structure of the songs is linguistic in nature. We believe that songbirds string together sounds according to a fundamentally different principle than the one human language is based on. "During their study, the researchers therefore made a distinction between language and speech, which is the way one learns to produce sounds.
From birdsong to baby talk
There is still a long away to go before this study finds its way into daily practice. "It’s important that we learn more about the fundamental principles of learning processes if we’re going to develop applications for our findings. Is it true that prosody is important for zebra finches as well as people? Does it help one learn more effectively? We may be able to use this knowledge to develop therapies for children having difficulty with language acquisition."
The birds provide a crucial starting point for studies involving humans. "When working with children, you obviously can’t do any interventions in their brains – something that’s a bit easier when dealing with the songbirds. With them, you can look at the brain itself and ask: what’s happening here? Gabriël Beckers’ work involves using electrodes to monitor brain activity. What happens, for instance, when you present songs that you have artificially manipulated to be more complex? We may be able to apply these findings at a later stage to help children with language development disorders."
Thanks to Dynamics of Youth, Bolhuis and his team were able to collaborate on this project with René Kager and Martin Everaert, linguists at the Faculty of Humanities. "The idea is to conduct further research on both songbirds and children. We have learned, for instance, that the more a bird learns, the more the information will 'migrate' to the left side of its brain. For the most part, that happens while they're asleep. This process has never been measured in human beings. It’s entirely possible that if you were to put sleeping children in an MRI machine, all kinds of interesting things are going on in their brains. I have already spoken with Serge Dumoulin, Professor of Perception, Cognition and Neuroscience, and Director of the Spinoza Centre for Neuroimaging in Amsterdam. He has also expressed interest in a potential collaboration."
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Dynamics of Youth
This project is a Dynamics of Youth seed money project. Within this research theme, researchers from different disciplines integrate their expertise to answer crucial questions for future generations. How can we help our children develop into balanced individuals, that are able to function successfully in a rapidly changing environment? As one of Utrecht University's four strategic themes, Dynamics of Youth combines excellent child research from all seven faculties.