Research into child development often involves answering questions that arise from previous research, or repeating research to see if the results are the same.
For some time, there has been a debate about if using words, or what scientists call ‘communicative sounds’ (this just means sounds that have similar tones and length to words and that are clearly intended as communication), help babies form categories.
To find out if babies have organised things into categories, they are shown a series of pictures (in these experiments they were shown pictures of either dinosaurs or fish). They are shown pictures all from the same category at first, then the test is repeated but a picture from the other category is included – so if the baby saw only pictures of dinosaurs first time, then second time around they will be shown dinosaurs, then a dinosaur and a fish.
If they look for longer at a picture of a fish than they do at the dinosaur, this shows they know it’s different and that they have a new category to learn about.
Research has been carried out using words, lemur sounds (yes as in the primates, we had to check!), beeps and birdsong to see if hearing these while looking at the pictures can help with categorisation. This study found words and lemur sounds helped, but beeps and birdsong didn’t.[1]
The lemur and birdsong experiments didn’t include a way of seeing if babies’ organised things into categories when they were shown the pictures in silence.
The researchers at Lancaster University who carried out this week’s deep dive study wanted to see if it wasn’t so much that words and sounds helped, but that unfamiliar sounds interfered with learning.[2] You might think lemur sounds are unfamiliar, (we did!) but according to scientists babies seem to recognise lemur sounds (and maybe other primate sounds) as communication.[1]
They based this idea on a theory called the auditory overshadowing hypothesis.
This theory argues that if babies hear a new sound while they are also looking at something new, they can’t focus their attention as much, so the unfamiliar sound makes it more difficult for them to learn.
In their experiments, the researchers showed babies pictures of either all dinosaurs or fish in silence – before showing them the pictures with one of the other category included, again in silence.[2]
They found babies did still notice when they were shown a picture from a different category, which suggests they had learnt these without the help of any sounds.
Then they did another experiment, this time they played babies sounds without showing them pictures, then showed them the pictures with these sounds. They found that now the sounds were familiar these beeps did not get in the way of the babies learning.
Even though this research looked at babies learning in silence – the researchers are clear that there’s lots of evidence that talking to babies helps them learn.[3] So, talk to your baby and tell them about new things, but also make space for silence when they’re playing and exploring
New sounds might get in the way of learning about things they see – when you’re playing with your baby try to reduce the other sounds around you.
Your baby will show you when they want to chat, and when they need a quiet moment to think.
References:
[1] Nuwer, R. (2021, 11 March). Baby talk and lemur chatter – but not birdsong – help and infant’s brain develop. Scientific American. Baby Talk and Lemur Chatter--but Not Birdsong--Help an Infant's Brain Develop - Scientific American
[2] Chan, K.C.J., Shaw, P., Westermann, G. (2023). The sound of silence: Reconsidering infants’ object categorization in silence, with labels, and with nonlinguistic sounds. Cognition, 237, Article 105475. https://doi.org/10.1016/j.cognition.2023.105475
[3] Westermann, G. & Chan, J. (2023, 22 May). The sound of silence. Lucid. The sound of silence | LuCiD