Does a finch babble like a human baby?
From singing zebra finches to babbling babies
Text: Fenna van der Grient
Photos: Bram Belloni
Children’s language development can falter for many reasons. Psychobiologist Sita ter Haar studies how to detect language development disorders at an early stage.
When children have a language development disorder, it is often not discovered until they are around three to four years old. This is a shame, argues Sita ter Haar (1982), a psychobiologist at Utrecht University. Ideally, you would intervene much earlier. That is why she is studying whether very early language development, the so-called babbling stage, can be predictive of how good children are at language later on. Songbirds go through a similar babbling stage, and it is a lot easier to monitor them. That is why Sita is combining baby research with research on zebra finches.
Why are you looking specifically at the babbling stage?
‘In that period, the second half of the first year in humans, a lot happens in learning and producing sounds. So, that is when you want to know if something is going wrong. Then you can intervene and make sure children get professional help in time, for example from speech therapists.’
What factors influence language development at this early stage?
‘There are a lot of them. Risk factors for language development disorder include premature birth, poor sleep quality, and smoking during pregnancy. The environment that you grow up in also plays a role, for instance, the culture or socio-economic status of the parents. This affects the quality of exposure to language: do you hear enough diverse language; do you have enough interaction with your parents? When you hear language mainly from a screen, for example, you pick up some of it, but much less than in real interactions.
I am also looking at the influence of sleep – right now only in birds. Sometimes the brain does not behave as it should during sleep. This may have genetic causes, or something may have gone wrong in development. For example, some children have epileptic brain activity when they sleep. You do not notice anything in their behaviour, but impressions are not stored properly in their memory. This can sometimes lead to a language disorder. Again, it is important to recognise this early on, so you can treat it.’
‘Like babies, birds first listen before they try things out: what can I do with my beak?’
What does researching zebra finches look like?
‘I try to keep that parallel to the baby research as much as possible so that I can make a direct comparison. Zebra finches are domesticated animals that live in groups, so you can very easily keep them in a lab. The advantage of that is that you can study them in a very controlled way, without bothering them too much. For example, you can monitor exposure to singing, or you can offer a particular song very precisely. You can also track development from day to day, where with babies we are already very happy with two measuring moments.’
How do you translate that to babies?
‘Songbirds have the same babbling stage that babies have. The sounds are obviously very different, and a song is different from our language. But that early stage of sound-learning is quite similar. Like babies, birds first listen to what is happening and then start practising. They start trying things out: what can I do with my beak? We can track from day to day what they do and when they can produce certain standard sounds.
In addition, we can study individual differences. We then look at whether we see similar development and differences in people.
I also look at the effect of disturbed sleep on song development. Zebra finches cope with this miraculously well, and it is something you just cannot manipulate in babies. We combine this research with brain studies in humans, in collaboration with UMC Utrecht. There, they do a lot of research on sleep deprivation, including in premature babies. They saw that the connections in the brain, the white matter, were reduced in those babies. We will now see if the same is true for the birds.
Conversely, in songbird research, we can again learn a lot from the systematic, almost mathematical way in which linguists approach language and language rules. With songbirds, it is usually more about watching what they do. I really enjoy that interaction.’
‘The CID is really a goldmine for follow-up research.’
What makes the CID a good environment in which to conduct this research?
‘There are experts from all different research areas. In particular, we work a lot with developmental psychologists and other linguists within the project. And I also use the YOUth database, which tracks lots of different measurements in children over long periods of time. It is truly unique. What is also special is that many studies include video recordings. They actually record them for a different purpose, for example, to study play behaviour, but I can use them to see how parents and children communicate. I can then lay this alongside song recordings of zebra finches.
After studying the predictive effect of the babbling stage on language development, we want to study, for example, how this development is influenced by socio-economic status and brain development. These are all things that these other people at the CID are working on and we can connect with. The CID is really a goldmine for follow-up research.’
Sita ter Haar is a postdoc at the Leiden Consortium on individual development.
This article is part of a New Scientist special issue about the Consortium on Individual Development, that will appear in September 2023.
