An interview with Dr. Melis Cetincelik
What was the main question in your dissertation?
In my dissertation, I investigated how babies learn language by focusing not just on the sounds they hear, but also on the visual and social cues they receive from the people speaking to them. Think of a caregiver talking to their baby: they are not only using words, but also making eye contact, using facial expressions, looking at things around them, and moving their mouths in ways that match their speech. These visual cues are a natural part of communication, yet we still know surprisingly little about how they shape early language learning. Do babies pay more attention, or learn better, when someone looks directly at them? Does seeing the mouth move help them process speech? My dissertation explored these questions by studying how babies respond to speech in different social and visual contexts.
Can you explain the (theoretical) background a bit more?
Many traditional theories of language development focus on what children hear. But in real life, language isn’t just something we hear—it is something we see, too. When caregivers and babies interact, there is eye contact, facial expressions, and visible mouth movements that happen along with speech. Theories of social learning and developmental psychology suggest that these visual and social cues help babies learn by directing their attention and giving extra support to understanding speech. Meanwhile, studies show that infants’ brains can tune in to the rhythms of speech, tracking for example syllables (e.g., the three beats in the word “ba-na-na”) and stress patterns (e.g., the middle beat in “ba-NA-na” is stronger than the other two). Tuning in to these rhythms may help them break speech into meaningful chunks. My research brings these ideas together by looking at how babies’ brains respond to speech when they also see the person talking, helping us understand how seeing and hearing together might support early language learning.
Why is it important to answer this question?
To understand how children learn language, it is important to look at how they experience it in real life, through both hearing and seeing. Studying how visual cues like eye gaze and mouth movements affect speech processing helps us understand how different types of information work together during early language development. This knowledge can also be useful in practice. If we know what helps babies learn best, we can give clearer advice to caregivers, and develop better early education strategies.
Can you tell us about one particular project (question, method, findings, implications for science or society)?
In one project, I looked at how babies’ brains respond to the natural rhythms of speech, like the beat created by syllables and stress patterns. For this, I used a method called electroencephalography (EEG), which involves placing a cap (like a swimming cap) with sensors on the baby’s head to record tiny electrical signals from the brain. This helps us see how the brain reacts to what the baby is hearing and seeing. I showed 10-month-old babies videos of someone speaking and measured their brain activity. I found that babies’ brain activity aligned with, or “tracked” the rhythms of speech. Importantly, I found that babies whose brains followed the rhythm of speech more closely at 10 months tended to know more words at 18 months. This suggests that picking up on rhythmic patterns in speech early on plays a role in how babies learn language.
What inspired you to choose your research topic?
I find it fascinating how babies go from not understanding a single word to speaking full sentences in just a few years. It’s such a complex process, but it seems to happen so naturally. Once I started learning more about brain and language development in my studies, I became especially curious about the factors that play a role in this rapid and effortless development. This led me to explore how visual and social cues help shape early language learning, and how the brain brings these different sources of information together.
Can you share a moment of significant challenge or failure during your PhD journey and how you overcame it?
A major challenge during my PhD was when the COVID-19 pandemic hit. I was just about to start collecting data for one of my studies, and suddenly everything had to shut down. Testing babies in the lab wasn’t possible for months, and there was a lot of uncertainty about when things could continue. Once we were allowed to test again, we had to rethink how we ran our studies. We wore masks, limited contact, and even replaced our usual bubble-blowing routine which we used to keep babies happy while putting on the EEG cap with a bubble machine to keep things fun but safe! Looking back, it was a strange but formative part of my PhD—it showed me how important it is to adapt to challenges and keep moving forward, even when things don’t go as planned.
What do you want to do next?
I am currently a postdoctoral researcher in the Department of Cognitive Neuropsychology at Tilburg University. My work focuses on how we process speech in challenging listening environments, such as trying to have a conversation in a noisy café. I’m studying how the brain manages to keep up with difficult-to-understand speech, what extra cues we rely on, such as seeing someone’s face, and how these abilities develop from infancy to adulthood.
