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In this episode of The Highlights, we're joined by Mira Nencheva, a graduate student in the Department of Psychology. We discuss her path to graduate work in psychology, the day-to-day of working with toddlers at the Princeton Baby Lab, and how the vocal pitch of a caregiver can affect learning early in life.
Brains, Black Holes, and Beyond (B Cubed) is a collaborative project between The Daily Princetonian and Princeton Insights. The show releases 3 episodes monthly: one longer episode as part of the Insights partnership, and two shorter episodes independently created by the 'Prince.' This show is produced by Senna Aldoubosh '25 under the 147th Board of the 'Prince.' Insights producers are Crystal Lee, Addie Minerva, and Thiago Tarraf Varella. This show is a reimagined version of the show formerly produced as Princeton Insights: The Highlights under the 145th Board of the 'Prince.'
Please direct pitches and questions to podcast@dailyprincetonian.com, and any corrections to corrections@dailyprincetonian.com.
[Theme music plays in the background]
Thiago Tarraf Varella: Hi everyone. My name is Thiago, and I'm a graduate student at Princeton University, and I am your host. The Highlights is a sister podcast to Princeton Insights in collaboration with The Daily Princetonian. Insights is a newsletter written by Princeton undergrads, grad students, and postdocs. We write about the most exciting and groundbreaking research being conducted here at Princeton in the form of short, fun, and easy to read reviews. We cover a range of topics including psychology, neuroscience, biology, computer science, and physics, to name a few. Make sure to check out our website at insights.princeton.edu. Today, I'll be co-hosting with Liza Mankovskaya. Say, “Hi,” Lisa!
Liza Mankovskaya: Hi. Hi, everyone. It's great to be here. So my name is Liza, I'm a graduate student in the Slavic department, and I care deeply about communicating scientific discoveries to a greater audience. So I wrote a review for the paper that we're discussing today on child directed speech, and I'm so thrilled to talk in more detail about it. This paper is written by a fellow Princeton graduate student Mira Nencheva, post-doc at the time; Elise Piazza; and Professor Casey Lew Williams in the Department of Psychology, and we're delighted to have Mira with us today. But, before we dive right in, I will let Thiago introduce Mira.
TTV: Mira grew up in Bulgaria where she first developed her interest in science. Later, she fell in love with psychology during her undergrad in symbolic systems at Stanford. She then received a Master's in Psychological and Brain Science from Dartmouth, and she's currently pursuing a PhD in Psychology at Princeton, where she is working with Dr. Casey Lew Williams at the Princeton Baby Lab. Over the years, the subject of her research has changed in many ways. The most striking change was the sizing of her participants. She went from studying elephants to working with mice, then adult humans, and finally now babies. In her graduate work, she's interested in the dynamics of communication between caregivers and children, and how those shape learning in the moment and over the course of development. So thanks very much for being here, Mira!
Mira Nencheva: Thanks for having me!
LM: Yeah, this is so exciting. So Mira, it's a very impressive bio. But could you actually tell us how your interest developed? Like, did you always want to study developmental psychology?
MN: No, definitely not. As you guys saw, I've dabbled in quite a few different things. So when I first came to the US for college, I was very set on becoming an immunologist. For whatever reason, I think that, you know, I'd studied bio, and I really liked learning about things related to like different kinds of blood cells. And so I thought that was really interesting. And then I got involved in this lab that was doing kind of a cross between immunology and psychiatry. And over time, I just like started realizing that some of the studies that I was thinking of, and getting interested in really had more to do with this behavioral aspect of it and more, you know, things related to emotions, just in general, how people are interacting in the world. And I took this psychology class my first year, and I got really, really interested in it. So we had to generate a study idea. And I just found myself kind of constantly thinking of different, you know, not very well informed, but different psych questions, and I just kept on kind of having all these questions and being interested in it. And it was really a kind of a moment of getting exposed to a field that I didn't really hear about when I was in high school, because we didn't really have this at all view of experimental psychology, I think we kind of stopped at Freud.
[All laugh]
MN: I thought that, you know, psychology was this thing where, you know, you lay on a couch, and you're talking about your feelings. But I think it was really interesting to me that you could use these scientific methods to understand behavior. And then from there on, I kind of kept on continuing to figure out what exactly about psychology I was interested in. So in the first lab that I was in, we were looking at stress response and elephants to earthquakes of all things! Then, I can look at decision making in mice, and so I did a summer doing that. Then like transition into human decision making in neuroscience, I did an honors thesis, looking at decision making and dating apps.
LM: We have a question about that!
MN: It was a fun project. But I wanted to kind of see the effects of smiles and different kinds of cues. But I think over time, what I got really interested in is this idea of social neuroscience, and what are the different cues, and how do they guide our attention to different aspects of a social scene. Then my senior year, I was applying to grad schools, and I had gotten into a program at Dartmouth, and I was going to continue on studying different kinds of cues and how they're shaping our attention. And then my senior year, after I'd already gotten into grad school, I took this class and it had to do with how kids were learning to talk and all these different, you know, aspects about how different cues are then affecting kids. And I was like, this is so cool, but you know, like, I already, I already have grad school lined up, maybe for a postdoc, I don't know. Yeah. And then over time, when I was doing work at Dartmouth, I think I started to realize that all these cues that I was so interested in were especially important for babies because as adults, we have language and so right now when I'm talking to you, I can communicate all sorts of things and just the kind of symbolic aspect of language, you know what these different words mean. But when it comes to really young infants, they don't necessarily have that in place. And so all these cues like different kinds of emotional expressions, intonation, all these different cues are really, you know, some of the most salient signals and are really the thing that allows the infant to figure out what to pay attention to. At which moment is something important happening? Because when you think of a child's environment, there's so many different things. So they kind of have to figure out what are, what are the moments when I'm going to learn something important. And so this kind of bug got stuck in my head. And then I had an opportunity to, I was talking to my advisor at the time, and I was like oh this is so interesting. And they were like, okay, you know, you can go off and spend a year in a developmental lab. We're going to fund you to do that. And then you can figure out what you want to do from there.
TTV: Was that a Ph.D. program?
MN: It was a Ph.D. program.
TTV: Oh, okay.
MN: Yeah, so then I switched. And then I came to Princeton.
TTV: Nice!
MN: I came here and I was like “This is it”!
TTV: Was it a transfer? Did you have to do the first years again?
MN: I had to, I had to, I mean, with PhD programs, you rarely ever fully transfer. And because I was doing a different line of research, I just started over. Yeah, but I feel pretty happy with what I'm working on. Now, I definitely have to say that even though I was like, “This is it”, there's still so much of “it” within developmental psychology. So I'm still trying to figure out what kinds of cues am I most interested in, what is kind of a unifying theme between the different things that I'm I'm interested in? So I’m still figuring it out, yeah.
LM: Well, but that's some commitment. I mean, changed programs to do development!
TTV: That's such an interesting story!
TTV: So is child directed speech the same thing as baby talk?
MN: Sort of, typically, when people think of baby talk, they think of people modifying the way that we speak and kind of speaking in ungrammatical ways. I think that's often you know, like, Oh, mommy say hi, or something like that, where it doesn't feel quite grammatical, I think child directed speech, there is a little bit of that going on, in the sense that I think in child directed speech, we do use certain words, that we sometimes don't as much use with adults. So for example, you would use a lot of diminutives, the kitty, the doggy, you know, like, you typically wouldn't talk that way to an adult, but they are mostly grammatical. But what child directed speech does is it has certain kinds of modifications that we do when we talk to babies. So for example, we tend to have quite shorter sentences, we tend to repeat things a lot, we oftentimes would use words in isolation. So you would say, dog, and then not necessarily embedded in the sentence. And also, in addition to these kinds of structural changes in the way that we talk, there are also a lot of things that we do in terms of our pitch. So for example, we would use higher pitch, if you think about talking to a baby, oftentimes, you're in a totally different speech register. Or dogs. But it is actually kind of interesting to think about what is the function of these modifications in pitch? You know, why do we speak higher? And you know, one thing is, for example, sometimes you would do some of these modifications when we're talking to somebody who doesn't speak English very well. So is it because babies don't speak English very well, or, you know, whatever language you're doing,
TTV: I appreciate it actually. It makes it easier to understand.
MN: Yeah so one thing is making it easier to understand. Another thing is, when we're thinking about, for example, dogs, oftentimes, what you're doing is really, you're conveying a lot of emotion. And so that's one of the things that people have argued is that infant directed speech really conveys this kind of emotional message that is, you know, a little bit easier to understand than necessarily the words that you're using. And then finally, the thing that was really interesting to us in this paper is that oftentimes people say that it's just more engaging. So really, what it's doing is it's keeping infants attention on the conversation. And so if you think about a baby, like you've ever interacted with one, oftentimes, they're looking at many different things. They're not necessarily paying attention to you always. And so oftentimes, what the parent is really trying to do is they're trying to communicate with the baby. So they're trying to keep their attention
LM: As a mom of a bilingual kid who needs to learn twice as many words. I'm so interested in your research, keep talking! How do I get his attention?
MN: Well, oftentimes, like using these different kinds of contours, it's really interesting. It's also I mean, it's also interesting to think about, depending on the age of the kid, depending on their language development, oftentimes, parents would be modifying how they're talking to them. And so there are certain cues that might be really useful early on, but then over time, parents have stopped doing them as much. So for example, repetition is one of those, there's really cool research showing that people will use a lot more repetition. But then as the kid learns more words, that stops being as helpful. And so they they actually start using a greater diversity of words and less and less repetition.
LM: And it’s all self taught, like every parent just figures it out on their own.
MN: Yeah so, that's also another question. Like, how? There's not a ton of research on that, but there's actually some really cool research out of Michael Goldstein's lab showing that if you put parents in a room and they show them a video feed of their baby, and they think that that's like a real video feed of their baby, and you show their baby's smiling and the moments when they're increasing their pitch, they're just gonna keep going higher and higher. Because obviously, you know, parents want their kid to be engaged and they want their kid to be smiling in them. And those are really rewarding cues. And so oftentimes, they would kind of keep doing what so yeah. Babies are making you learn!
LM: Keep doing what works. Yeah, that's amazing. And so specifically in terms of pitch, so you we know that this paper is about pitch primarily, but why did you decide to focus on pitch? And you mentioned that researchers say, well, it's more engaging. So how do these two things you already mentioned that, but could you sort of transition us to the particular topic of the paper? The different pitch contours?
MN: Yeah so, the reason why we focus on pitches is that it's one of the first things that you notice about child directed speech, and it's pretty, it's quite universal across many different cultures, that we tend to have these exaggerated pitch contours that we have tend to have this higher pitch overall. And also is this really dynamic cue in speech, it's non-stop changing, especially when you're talking to an infant. And so the puzzle that I kind of had in my mind is that oftentimes we say, okay, infant directed speech is more engaging. But the way that we're doing this is we're basically looking at how long babies are listening. So in a typical study, you would play them a stream of infant directed speech, and you see how long it takes them for them to like, look away, and not be interested in hearing this speech. And then similarly, you do the same thing for adult directed speech with, you know, it's quite a bit more monotone. And then you see how long it takes them to look away and not want to listen to it anymore. For me, engagement, oftentimes, it's really this kind of moment to moment thing. So it's not really you know, like, how long I mean, one aspect of it is how long am I going to listen to something but what's especially important for learning is like, how much am I paying attention in this specific moment? When you're introducing this novel word, like, how much am I tuned in? And how ready am I to receive the auditory information? How ready am I to receive the visual world around me? You know, if you're referring to an object, for example. And so what we wanted to do is to look at pitch, but in this kind of more moment to moment scale. And really to understand when are infants tuning in. What are different moments of variation in pitch, the different kinds of contours, you know, whether a pitch is going up or down, trying to figure out, you know, how are these moments really shaping children's ability to learn? Because this is a question that as a field we haven't really looked at as much, especially when it comes to these kinds of auditory variations.
LM: Yeah, impressive.
TTV: So, obviously, you're working with children and doing experiments with children. How is it?
MN: Ah, it's really, it's really fun. I mean, I think one of the reasons why I also liked developmental psychology, in addition to the questions being kind of interesting is that it's this really interesting puzzle of how do you figure out when a baby's engaged? Because oftentimes with you know, with adults, you can just ask them, you know, how are you feeling right now? How interesting was this? And, you know, with adults, there's a lot of challenges still, with them not being honest. But I think with infants, you have to have this really creative research design to get at what is going on in their heads. And so I think that's something that is a really fun puzzle. And obviously, also babies are very cute. And we get them for a short period of time. And so we don't, you know, we only get the cute side. But yeah, we do all sorts of things like creating fun images to be on the screen. So there's this kind of creative aspect of it.
TTV: Are there any memorable experiences of situations that are like really funny or really cute?
MN: Oh, yeah, I mean, oh, there's a lot of like, I think just the day to day, oftentimes, like babies would just not do your experiments. So there's all sorts of fun ways in which they do it. Sometimes they would just like, if they're a little bit older, they would just walk away. Or they would spend the whole study looking at their shoe, which is very interesting. Or like trying to communicate with their mom and his lab, they're sitting and they would like turn around and like, try to talk to the mom. I've had a lot of times like babies just being handed to me. And I'm like, even though I work with babies, I don't like I don't have a kid. I don't know how to do this. But yeah, so it's been really fun to just get it. Also just really fun to interact with families and parents like it's, it's actually pretty rare in adult research, for people to really want to be sharing as much stuff with you. I think oftentimes, when we have parents in the lab, they really are interested in the research, they want to talk to you about their experiences, and you oftentimes get really interesting kind of intuitions from parents as well.
LM: This is so interesting. So you actually get you know, some ideas from what parents tell you.
MN: Sometimes they're right in there. Sometimes they're like way off. You know, social psychology is full of things where we think that that's very intuitive and is the case then it turns out, it's not quite.
LM: Do they want to follow up? You know, after you've studied everything, do they want that? Like I do, do they want to know, so how do I talk to my child? So can you give me some recommendations?
MN: Yeah, they sometimes do. And they're also sometimes they're interested in like, how did my kid do? And so it's sometimes it's sometimes kind of difficult to tell them because a lot of these measures like, I don't know, in the moment, like what your kid learned, like, we're gonna analyze it afterwards. And oftentimes, it's, you know, we average over many kids. Yeah, we just send them a newsletter every year with all of our studies in kind of a digestible format, which I think is really important because we really want to make sure that the families are getting something out of it. Like they're so interested and they're so wonderful. Like all the families that we worked with are really great. And they're, you know, they're taking time out of their very busy days. You know, you know, as a mom, it's like, it's hard to find the time.
LM: It’s like you have both research and research communication built in.
TTV:
What about wearables? Do the babies have to wear something? Is it easy to make them wear?
MN: It's really difficult to make them wear things, especially hats, they really don't like to wear hats. So something like functional and your infrared spectroscopy, it's measuring kind of how blood is flowing around the brain and which parts of the brain are receiving more or less oxygen at any moment. And that kind of serves as a proxy for neural activity. So the neurology method I just mentioned, it can be challenging to get babies to wear a hat, normally, you just kind of have to have the cap ready, and then you just like, pop it on, fingers crossed, that they're distracted at that moment. And then for eye tracking, when the way that our eye tracker works is you have to put a sticker on them. And that allows them to kind of move around because you can't really keep them still and allows them to move around and for the eye tracker to figure out how far are they from the lens, you know, and then estimate their pupil size, but they sometimes don't like the sticker. It's just so so heartbreaking. Sometimes it just would put the sticker on and they're just like start crying, like you just put something really awful on them. And they're like it don't like the sticker. So there's different kind of ways to.
TTV: What do you do in this case? Do you just cancel the session?
MN: So we have some tricks to before that happens. I think if a kid is really like, if they're crying, like at any point in the session, they just don't want to continue, you would think that, you know, it's like the parent consenting, they're really like a one or two year old, they'll let you know that. We don't force them to do anything. And I think that's pretty important to us as well, because they are, you know, they're human participants. And for any kind of human subjects research, you really want to make sure that there's consent from, from the person who's doing it, regardless of whether they're like 2 or you know, they're 20 something. So yeah, so we really want to make sure that they're comfortable. So if they're crying, and they don't like it, then we just hang out with them for a little bit. And then they go home, and we give them you know, T-shirts and books. But I what I typically do is our stickers have kind of a like a black and white circle pattern. And then we have this little little zebra on the room. And so I call this zebra room, and oftentimes it's like, oh, you know, when we go into the zebra room, we have to dress up like zebras, sometimes, you know, the parent will put the sticker on somewhere on their body. So it feels you know, like everyone's doing it, sometimes I would put it on to so now we're all zebras and different ways to do it. But I think usually they're fine. Like some kids really like stickers. And actually, the problem is that they want to put stickers everywhere. And you can do that for the eye tracker. They're like, oh yay, stickers. I'm just gonna put them everywhere. I'm like, can't do that.
LM: So could you tell us more about, you know, what do you exactly do with this method? In this paper?
MN: Yeah, so typically, when people use pupillometry. So just for people who don't know, what pupillometry is, is basically we're measuring how wide your pupils are getting and how they're changing in size. So how much they're dilating and constricting over time. And what's really interesting is the neural mechanisms that are controlling this are in centers of the brain that are really tied to a whole lot of things. So they're tied to how kind of intensely you're feeling in the moment, they're tied to things like you know, how much like stuff you're doing in your heads, if I'm making you do like, you know, all sorts of math in your head, while you're trying to, you know, record a podcast, your pupils dilate, because you're gonna be experiencing a lot of cognitive load. And so they're tied to all these different aspects in terms of how we're processing things. And so oftentimes, what people would do is they would have some sort of a stimulus, you know, some sort of like an image, maybe like an emotional image. And then they would measure how your pupils are dilating. What we're doing here is a little bit different in the sense that we're not, you know, showing them kind of a one time event and then seeing what happens afterwards. We really are interested in these really kind of moment to moment fluctuations in how the kid is processing speech. And so what we're doing is we're recording these changes in pupil size over the course of, for example, a story or a sentence. And there's something really interesting. I didn't come up with this. There's a really cool paper by Tanya Wheatley and Olivia Kang from 2017. And what they came up with as an idea is that, you know, when we're all paying attention to the same stream of audio information. If you're listening to this podcast right now, your pupils are going to be responding to these moment to moment changes in what you're hearing. And if at the same time, for example, you're not actually paying attention to the podcast, you're like reading your email, or doing something else or you're even on like a, you know, on a Zoom call in the background and you actually pay attention to that. Your pupil dilations are actually going to be coupled not to what you're listening to in terms of the podcast, but they're going to be coupled to something else. So they really are responding to the thing in your environment that you're tuned into, and you're paying attention to. And so there's kind of an important byproduct of this is that if, like, let's say, me and Liza are both listening to the same thing, and we're both really paying attention at the exact same moments, our peoples are going to be doing the same thing. And so the idea in this paper in 2017, was that, you know, when people are listening to emotional stories, their pupil dilations tend to synchronize at these moments when, you know, it's the most salient moment in the story. So I think they had one where it's kind of the build up to like a first kiss. And you know, in the moment when it's like, oh, it's the culmination, you know, sitting under the stars, and it's about to happen. And so in those in that moment, everyone's pupil dilations are like, oh yeah, synchronized or paying attention. And so yeah, so what we're doing here is that we wanted to use this in toddlers. And the reason why you wanted to do this is that in toddlers, we have so few measures of how engaged they are in the moment. And so this really allowed us to not only look at how engaged they are, throughout, you know, a story that is told in infant directed speech versus adult directed speech, but also how engaged they are over the course of a single word that has a different kind of contour. So that was kind of our idea to really have this more precise measure in terms of, you know, the timing of when they are really engaged.
TTV: And what did you want to test with this engagement?
MN: We wanted to see, first of all, which moments in infant directed speech are more engaging, at least in terms of pitch, this is a very kind of first step in this, there's obviously a lot more going on in infant directed speech beyond pitch, but we wanted to see which moments are most engaging. So you know, what kind of variation whether the pitch is going up or down. And what we wanted to see is how that is affecting kids' learning. So if presumably, they like this is an actual measure, because we weren't sure how this is gonna work with the babies. If this is an actual measure of engagement, then in the moments when they're most engaged, you would expect that they would also be learning better. So in the last study, we introduced these novel words, they're all made up words, these made of objects that come with them, and we try to teach them to toddlers with these different pitch contours. And so then afterwards, we looked at whether the words that they show this kind of higher, more similar pupil response to other toddlers who are listening to the same word at the same moment, if those moments when you know, they're paying the most attention, if they were then related to better learning, so if they then learned those words.
TTV: How do you measure if they learned something?
MN: So the first part of the study, we would show them an image of, let's say, some sort of a made up like animal, and I'm saying this animal is called, like, bozhou. And so I would just keep saying, like, oh, look, it's bozhou, like, oh, who's that? Bozhou. And so I would keep saying that, and over time, babies would learn that word, presumably, maybe. And so we would do this with several different made up words like this. And then afterwards, in the second part is when we're testing whether they actually learned so this first part is kind of the training part. And so then we would show them two images side by side and one of them is bozhou. But the other one is the dudax, just another kind of made up animal, for example. And we would ask them, like, oh, where's the bozhou? Do you see it? And if their eyes spend most of the time on bozhou, we would presume that they've learned that Bosu is that image rather than the other one. And we would do it in all sorts of, you know, combinations of different side. And obviously, make sure that we vary the images, because sometimes, babies would really like to look at the bozhou image, regardless of what we call it. So we want to make sure that that's not why they're looking at it. So we make sure that we kind of switch things up. But that's usually how we measure it. So we would show two things side by side. And we on the eye tracker can see, you know, how long did they spend on this image? How quickly do their eyes get there?
TTV: Are these words something they remember in the long term?
MN: There's a lot of studies that show that no. After such a short lab study, even if you give them something like 10 or 15 minutes a break, and then you test them again, they'll be like, I have no memory of anything.
LM: So not only do you need to use the right pitch of the parent, you also need to repeat.
MN: Yes, you definitely need to repeat. So they won't learn them, especially at this age, they won't learn them just from a one shot kind of thing.
LM: And so circling back to the actual pitches, so we understood the importance of attention. But could you walk us through what do these pitch contours do?
MN: Yeah, so we first wanted to start with a little bit of a blank slate and in terms of not assuming what those pitch contours are. I think in retrospect, when we look at what they are, it's kind of like, I guess, I don't know what else pitch could be doing like in such a short period of time over the course of a word. But what we did is we went to this huge database of child directed speech and we looked at parents pitch during nouns, and we just isolated you know, the pitch during hundreds to like over 1000 nouns. And we did this kind of analysis that allows us to pull out what kinds of groups are in there. This is called a clustering analysis. And we saw that there were these several different kinds of pitch that parents tend to use. I mentioned them earlier. So there is the rise, “this kitty looks cool.” The fall, “this kitty looks cool.” And then it's like a hill contour, “this kitty looks cool.” And a valley contour, “this kitty looks cool.” What is interesting is there's some prior work that shows that parents do use some of these contours in very specific ways. For example, the hill contour that we found that there was this kind of heightened attention to and overall better learning for is a contour that parents use to emphasize.
LM: Could, could you demonstrate?
MN: The hill counter is actually the easiest one to do, because it comes the most naturally. So it's like, “kitty,” you know, like, you go up and then down. So you know, for example, you'd be like, “look at the doggy,” you know, and that's oftentimes like that word kind of pops out a little bit. And so it's used for it's used for emphasis. It's oftentimes something that parents would use when they're introducing a new word. So for example, if you have them, like read a book, and we have these, like new words that we've popped in parents would use that contour. There is some prior research showing that, you know, if they're reading a book, and we highlight certain words, or like certain important words, they would use that kind of contour with it. So it's kind of interesting that it seems like parents are using this contour to emphasize and so there's this kind of chicken and egg problem that I don't have the answer to which is: are parents using this contour because babies are paying more attention to it? Or is it that babies are paying more attention to this because parents are using it? So if they're associating this with some kind of important information, maybe over time they learn this. It's also possible that it's both, but we don't, we don't really know.
TTV: And what is the least interesting contour?
MN: It’s the valley contour, which is really difficult to do on the spot. It occurs in natural speech. And when it occurs in a natural speech, it sounds natural, but when you try to do it by yourself, it just sounds really weird. And that's one of the reasons why in our second study in the paper, we looked at, you know, we were looking at these contours in these like sentences that we recorded. And we made these like super controlled recordings just to make sure that like, you know, the average pitch was the same even though it's varying over the course of the noun. And at least Piazza, who is the co-author on this, she is amazing. She's also now an Assistant Professor at Rochester. You should go check her out, she's great. But she had musical training. And so luckily, she was recording these stimuli. And it took us so long to get them right, to record them, and to make sure everything was controlled, and to make sure that they were like really closely replicating the kinds of groups that we saw earlier. We wanted to make sure that this isn't just you know, the results that we're seeing in terms of attention isn't something about our sentences being really weird, sounding kind of robotic and odd. Especially, we had this one flat contour, which we wanted to just like add as a baseline, but it just sounded something like, “kitty,” because it’s so hard to keep your pitch the same, like exactly the same, you know, and so it was obviously pretty artificial. So what we did is we went to this natural story that we had recorded in child directed speech, and we found the words that have these contours, and we managed to replicate. So to show the exact same pattern of the extent to which kids were paying attention to these different contours. But in this naturally occurring, thing that didn't sound weird.
TTV: So to wrap up, what is the take home message of the paper?
MN: I think it's, well, it's a few things that I think the main kind of contribution, I think was a little bit more of a methodological one, as in, you know, we can use this method of really understanding when babies are paying attention on this moment to moment scale. And we can use it to examine all sorts of things, pitch is just one thing. So I think this is kind of a case study. I think the other thing is that babies really seem to be really tuned into the dynamics of speech. So there are these moments that are really optimal for learning. And it's not necessarily just because something is child directed speech, it means they're paying attention 100% at every single moment in their learning equally at every single moment. Really what it is, is that learning happens over these many moments in time. And so it's really important to understand what are the characteristics of the moment. And you know, we started off with pitch, but there are so many other things that are happening both within speech but also within the environment in which parents and children are interacting in.
LM: What are next plans? Where do you go next after those pitches and their effects?
MN: Yeah, so we're, we're doing right now an analysis. It was a collaborative project with many labs. And so we're using their data where they looked at this kind of comparison between infant directed and adult direct speech. And so what we're going to be looking at is, you know, the extent to which these different features in the beyond just pitch, are driving attention in different moments. And we're also going to be expanding to other kinds of cues. So things like, you know, facial expressions, or even, you know, things related to the vocal expression of emotion or you know, the extent to which they're using different kinds of words or things related to the structure of speech. So really trying to put together all these different kinds of cues that are available to children that are dynamically changing from one moment to the next to understand what are these moments that are optimal for learning?
LM: Well, I'll certainly stay tuned!
TTV: Yes, me too! I think we can call it a day then. It was very nice having you here. Thank you very much for talking with us.
MN: Yeah, thank you so much. This is really fun to talk to you.
LM: I feel like it was a great conversation. Thank you so much, Mira.
MN: Yeah, thank you so much!
TTV: This episode of the highlights was written by Thiago Tarraf Varella and Liza Mankovskaya. It was produced by Isabel Rodriguez and the 145th Managing Board of The Daily Princetonian. For more podcasts and other digital media from the Prince, visit www.dailyprincetonian.com. Many thanks to Mira Nencheva for speaking with us. To read more about her work, check out the Princeton Insights article covering her research, which can be found in the description of this episode. Thank you for listening, and until next time!
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Transcribed by https://otter.ai