9 Reasons Your Child Should Participate in Language Development Research

One day your child comes home from school or camp with yet another a stack of papers to be signed and returned at your earliest convenience. At the top of a sheet stamped with the local university’s logo, you see the heading: “Consent to participate in a research study.” Your child has been invited to participate in a linguistic experiment. You are instantly wary; perhaps you have watched a documentary about the Stanford Prison Experiment, read an article about MK-Ultra, or followed any of the numerous scandals relating to personal data harvesting on social media platforms. Let’s be honest, there are plenty of reasons to mistrust scientists, especially if you or your child are a member of a marginalized community.

That being said, in this day and age, language acquisition experiments are really nothing to be scared of. There are no medical procedures involved, no psychological warfare, and no abuses of data (as far as I’m aware). On the contrary, it’s often pretty fun for the children, not to mention extremely helpful for people whose careers depend on successful research projects. So, I thought that I would put some information out there to attempt to quell the general public’s fear of the word “experiment” and help caregivers make a more informed decision about when and how to allow their child to participate in language acquisition research.

1. Every child has a something unique to contribute

No two children have exactly the same language experiences, and that creates a lot of potential for variation in the way that they acquire and use their target language(s). While some differences — such as mono- versus multilingualism — are more obvious, there are plenty more subtle variations in the ways that children experience language. For instance, the way that adults speak to children (i.e. the words they use, common sentence structures, and even the rate of speech) varies wildly both across and within cultures. In some families, caregivers may engage in a constant dialogue with their children from Day 1, even if the conversation is mostly one-sided during the early years. In other families, talking to an infant who is incapable of responding might be seen as strange. Even birth order can have an effect on the way that children experience language — older siblings are often a significant source of language input for younger children, which means that they provide a lot of primary linguistic data for their younger siblings to work with. In order to obtain a well-rounded view of the ways that language develops and the limits of its variation, we have to take all of these factors into account. Your child’s unique background can contribute to that knowledge in a huge way!

2. They might learn something about the language(s) they speak

One of my favorite things to do with older children is to ask them what they think I was trying to find out after an experiment is completed. They’re almost never correct, but it does prompt them to reflect on the language that they used throughout the course of the activity, and in doing so they often make pretty astute observations. Even when they struggle to understand or produce a particular structure, the repeated exposure throughout the experiment allows them to grapple with the way that a specific meaning is mapped onto a linguistic form. It’s also not completely unusual for children’s performance to improve during the course of an experiment — there is definitely an educational function that should be more systematically studied.

3. All materials are safe and appropriate for use with children

All researchers working with human participants have to submit detailed proposals to an ethics approval board before they are allowed to collect data. For vulnerable populations such as children, the vetting process is even more extensive. All of the experimental materials (meaning the pictures that participants will see, the sentences they will hear, and anything else the child will be exposed to during an experiment) must be submitted and approved by the ethics board of the university and/or country, and these organizations don’t just give the green light to anybody. In the US and Europe (at least the countries I’ve worked in), anyone who will be in direct contact with children must undergo the same screening as public school staff, which typically involves fingerprinting and a background check. Institutions put a lot of effort into making sure that research studies are conducted ethically, and those who violate ethics policies can be subject to extensive disciplinary measures, including legal action.

4. Your data is protected

When your child participates in an experiment, some personal information might be collected in order to be used in the analysis later on, in addition to any of the results from the experiment itself. All of this information must be stored in a manner compliant with data protection laws (i.e. the GDPR in EU countries) to ensure that it is not misused. In practical terms, this means that information like what language(s) your child speaks, their age, and other relevant demographics might be collected and stored on a server at the university, but they are not linked to your child’s name. Instead, each participant in an experiment is assigned a random identifier, like a sequence of numbers, a pseudonym, or some other code. The only document that contains any real name is usually the consent form (since you have to sign it), which is stored as a physical copy in a file cabinet somewhere, or else on a separate, encrypted hard drive. Institutions have strict guidelines about how experimental data can be stored, and the specifics should be outlined on the information sheet that you receive before consenting.

Researchers also cannot use your data for any purpose other than what they told you it would be used for: for example, if the consent form says that the data will be used for publications relating to XYZ Research Project, they can’t then give it to a colleague to use for ABC Project, even if that colleague is in the same department. If it says that the data will be used in scientific publications, then they can’t post excerpts on social media to show their friends how cool their job is. And of course, they can’t sell it to Big Tech to supplement the egregiously low wages that the university pays them. Furthermore, you are allowed to withdraw consent at any point before or after the experiment, in which case the researchers are legally required to promptly delete all your data. All you have to do is email the primary investigator (PI), whose contact information is listed on the information sheet.

5. You might earn some money

Lots of labs have a budget for reimbursing participants, even if they do not complete the entire study. Of course, we aren’t allowed to give children actual money, but we will often give them a small toy or some stickers to thank them for their time. Alternatively, caregivers might receive monetary compensation or a gift card.

6. You can do many of the studies online

Thanks to the pandemic, online studies are more common than ever before. There are numerous websites where you can sign up to participate in developmental research from the comfort of your own home, such as MIT Lookit. That’s a great way to keep the kids occupied for a few minutes during school vacations.

7. It’s fun!

Acquisition researchers spend a lot of time making their experiments as fun and engaging as possible — after all, you aren’t going to get good data if the kids are just trying to finish the activity as quickly as possible. Most experiments nowadays are basically games with an underlying purpose. I always find that when I collect data at schools or summer camps, only a handful of families initially consent before I start coming in regularly. Inevitably, the number of willing participants increases exponentially as I spend more time with the kids, through no conscious effort on my part. Once the children discover that the experiment is basically just a language game, they tell their friends about it, and suddenly half the class is going home and begging their parents to let them participate. I’ve had plenty of kids ask me if they can play the games again (and occasionally I oblige, if I have time). They genuinely enjoy figuring out the “word puzzles” and winning the games that we have in store for them (spoiler alert: the games are rigged so they always win).

8. Findings from language development studies can have huge implications for educational materials

Lots of findings from acquisition research can be used to improve the language and materials that are used in education. Have you ever wondered whether your child really understands the explanations in their schoolbooks? Or how children learn to label abstract grammatical categories like “noun” or “adjective”? Linguistics research can help answer that question and indicate better ways to formulate explanations and teach lessons on grammar, reading, and writing. There are entire conferences dedicated to this exact topic, such as LiDi.

9. Findings from language development studies can have huge implications for diagnosis of language disorders

Did you know that multilingual children are at risk of being incorrectly diagnosed with a language delay? This is because most of the tests and screening materials for language delays are based on the “normal” developmental trajectory of white, upper-middle class, monolingual children. For a long time, it was assumed that bilingual children had weaker linguistic knowledge than same-age monolinguals in each of their respective languages. This was actually because researchers had only accounted for their knowledge of one language, not both. When you consider the words and structures a bilingual child knows in both their languages, oftentimes they come out ahead of their monolingual peers. This trend of misdiagnosis is a big problem for lots of reasons: first, it means that many (misinformed) pediatricians and teachers continue to encourage parents not to teach their child their native language because they believe that it is somehow damaging to their development. Second, it means that resources are misallocated to help children who don’t actually need any help! On the other hand, without adequate understanding of how multilingual children may differ from monolinguals, we might also miss out on some other signs of disordered language that don’t typically present (or present differently) in one population or the other.

Suffice it to say that if caregivers hadn’t consented to let their bilingual children participate in research, we might never have made that critical discovery about bilingual development. If only certain demographics of children are participating in linguistic research (like monolinguals, only children, or professors’ kids), we aren’t obtaining a sample that truly represents the population as a whole, and all of the conclusions we draw might be biased against other demographics.

Bonus: You might help someone get a degree

It may seem obvious, but it is worth noting that lots of language acquisition research is conducted by students, for whom completion of the project is a requisite for their degree. That means if they don’t have participants, they don’t get a degree (or they have to go back to the drawing board and waste potentially years of work). Finding willing participants is one of the hardest parts of conducting acquisition research, and it has only gotten harder in these post-pandemic times. If you have the time and resources, and you think your child would enjoy it, you might consider helping out your friendly neighborhood acquisition researcher.

Proposing the Research

Hello world! Long time no see. You might not be surprised to know that this whole “getting a PhD” thing has been relatively time-consuming, and has left me with minimal energy reserves for frivolous blogging.

Nevertheless, I am back and ready to use this platform for more self-reflection and discovery. Maybe it will also help me see where exactly I need to be doing some more review, and it will help you to find out what I’ve been doing for the past seven months. Yay!

So, what have I been doing with all my time, if not trying to come up with phonetic analyses of ventriloquism or explaining the historical development of homophony to my father? The answer, in short, is that I’ve been writing and refining my research proposal. If you tuned in but actually don’t care to read the full essay, that’s all you really need to know. Otherwise, read on to find out more about what that means, and what it is I’m proposing.

For those of you outside academia, the research proposal is exactly what it sounds like: a 20-30 page paper in which I outline what my dissertation will be about and why it’s a topic worth researching. “Here’s what we know,” “here’s what we don’t know,” and “here’s how I plan to find out,” in other words. In my particular program, there is no deadline to complete the proposal, but we’re strongly advised to get it done within the first year, because it helps you establish a trajectory and also helps your supervisor/other professors to see that you’re on the right track. Seeing as I officially started in November last year, I’m more or less right on time.

For the most part, I’ve just been whittling away at my various ideas and cobbling together a coherent roadmap for the remainder of my studies. Back in June, I gave a presentation at my department’s research colloquium to get feedback on the initial ideas for my proposal, and then in July I started drafting. Now I’m finished with the first draft and waiting for feedback from my supervisor, and then I’ll rework it and submit it to the university.

What I’m Actually Proposing

As you may recall, my dissertation topic deals with recursion, which in linguistics, is the idea of embedding a syntactic structure inside itself. For example, in an utterance like Wendy’s boyfriend’s ship’s captain, each instance of [noun]’s is embedded in another; thus, you have to figure out what/who Wendy’s boyfriend refers to before you can figure out what Wendy’s boyfriend’s ship refers to, and so on. The types of structures that allow recursion vary across languages, and are relatively challenging for children/foreign language learners to acquire.

People have looked at the acquisition of recursion in a number of languages including English, Mandarin, Tamil, Japanese, Spanish, and German, and have proposed a number of different explanations for why it’s so difficult for children and language learners. One interesting aspect of this prior work is that the age of acquisition – that is, the age at which most children can reliably interpret recursion like an adult – varies pretty extensively, from as young as four to as old as seven. This variation is not only seen across languages, but also within languages. I would hazard a guess that this has to do with the experimental methods and differing definitions of “acquisition,” but there could also be some important differences between the structures and languages themselves. These potential differences are one thing that I am interested in, and that I want to look at for my doctoral work.

The other major question that my research deals with is the potential impact of acquiring two languages at once on acquiring recursion, particularly when those two languages differ structurally. This taps into a major focus of contemporary bilingual research, which is the degree to which a bilingual child’s two languages interact with one another throughout the course of development. In the past 2-3 decades, we have found that bilingual children’s development does tend to differ from monolingual children both qualitatively and quantitatively, but the extent of and the contexts in which these differences occur have yet to be determined.

There have been three prior studies on bilingual children’s acquisition of recursion compared to monolinguals, each with a different result: one study (Leandro and Amaral, 2014) showed that the bilingual children did better on a comprehension task compared with monolinguals of the same age. Another study (Avram et al., 2021) found that seven-year-old bilinguals performed less accurately than seven-year-old monolinguals in a different comprehension test. And finally, Pérez-Leroux et al. (2017) found no difference in the frequency with which bilingual and monolingual children used recursive phrases to describe pictures. In other words, being bilingual could accelerate, delay, or have no effect at all on the acquisition of recursion. 🤷‍♀️

Of course, a few things that may have impacted the outcomes of previous work, which I hope to control for in my own experiments. Perhaps most important is that each of the aforementioned studies looked at a different language pair: the first one looked at English and Wapichana, the second at Romanian and Hungarian, and the third at English and Spanish. Therefore, characteristics specific to those languages may have influenced the way that bilingual kids interpret or produce recursion. One possibility that was mentioned in the L+A and the Avram studies is whether the target languages differed in terms of branching direction. In the L+A study, where the bilinguals seemed to outperform monolinguals, both languages had left-branching possessives. On the other hand, in the Avram study, where the bilinguals did not do as well as the monolinguals, the children’s two languages had conflicting branching directions for the target structure. This led the authors of both studies to propose that structural similarities could either accelerate or delay bilingual children’s acquisition of recursion.

This proposal regarding recursion taps into a more general hypothesis by Hulk and Müller (2000), who suggest two criteria for determining whether a particular structure will be vulnerable to cross-linguistic influence in bilingual development:

1. The structure is not “purely” syntactic, but involves a connection between syntax and some other module of grammar;
2. There is a (perceived) degree of overlap between the two languages

If a particular phenomenon in language meets both of these requirements, they argue, then it is likely that the bilingual child will show evidence of one language influencing the other. Setting aside the first criterion, #2 predicts that, if a bilingual child encounters a recursive structure such as Wendy’s boyfriend’s ship’s captain in both their languages, they might use evidence from one language to support their development in the other.

Alternatively, the child might speak a language where the branching directions differ: imagine that in Language A, the “head” of Wendy’s boyfriend’s ship’s captain is “captain,” like in English. But in Language B, the head of the phrase is actually “Wendy,” and everything else is a modifier! This is confusing, and may cause the child to incorrectly analyze the structure in one or both languages. They might decide to go with the “head = last” approach, as in Language A, and therefore misinterpret the meaning of the phrase in Language B, or vice versa. They could also decide to just try both interpretations in both languages, resulting in a lower success rate in both. Of course, ultimately, they will sort it all out, but the path they take to get there is what interests me.

I’m working on the design for an experiment now that will address the comprehension of two types of recursion by children acquiring English and Mandarin Chinese at the same time. The two types of recursion differ in terms of branching direction: possessive structures, such as Wendy’s boyfriend’s ship’s captain, are left-branching in both English and Mandarin, with the head of the phrase at the end. Locative structures, on the other hand, are left-branching in Mandarin, but right-branching in English. For example, an expression like the cinema next to the post office next to the bank in English is a mirror image in Mandarin: 银行旁边的邮局旁边的电影院 bank next-to post office next-to cinema. This might constitute confusing evidence for a child, who might prefer to assume that all structures in both languages are left-branching, and therefore may have more trouble acquiring recursive locatives in English.

Thus, if there is an impact of branching direction on the acquisition of recursion specifically, then we would expect the children to perform similarly on possessives (which have the same branching direction in both English and Mandarin) but not on locatives (which are right-branching in English but left-branching in Mandarin). This is what I hope to figure out using a comprehension “game.”

That’s the bare-bones sketch of my current plan and related activities. Last week, I’ve spent most of my time reading up on theories of bilingualism and cross-linguistic influence, and will continue doing so this week. After I have re-worked my proposal and gotten the approval from my supervisor, then I will start ironing out the details of the experiment, which is a fun but time-consuming process that probably warrants its own blog post(s). And then, at some point after that, I will be ready to start recruiting participants.

The good news is that I feel like I know what I’m doing more each day. Stay tuned to see what happens next!

Recursion: What it is and why I won’t shut up about it

It’s a running joke between me and my close friends that any and every instance of recursion has to be explicitly pointed out in the course of our day-to-day existence. My partner and I will dramatically gasp every time we hear someone on TV use a construction like “my friend’s brother’s blah blah blah,” or when someone says that they think that she said that he wanted to go to the movies, not the mall. On one hand, it’s just one of those jokes that gradually became instinct as time wore on; on the other hand, it’s thrilling to notice real-life instances of recursive structures when you least expect it, especially given how little we talk about it outside of academic circles.

I started working on a project related to recursion when I was an undergrad and haven’t really stopped since, simply because there are so many aspects worth exploring, both linguistically and cognitively. Unfortunately the term isn’t all that transparent when you try to put it in general terms, which has the unfortunate side effect of boring nearly everyone I talk to. Since I’m currently in the literature review stage of my PhD proposal on this exact topic, I thought I’d hold myself somewhat accountable by writing a little about what exactly recursion is, why it’s interesting, and what about it I specifically want to look into in the coming years.

In Vision, CompSci, and Math

Recursion = putting something inside itself (Image source)

Recursion refers to the general concept of using the output of a process as the input for the same process (AKA “putting something inside itself”), which a number of cognitive scientists believe is an ability unique to the human mental faculty. One of the most straightforward examples of non-linguistic recursion is the Matryoshka doll, which opens up to reveal another, smaller doll which opens up in turn to reveal yet another doll… rinse and repeat until you have a tiny little pebble-sized version of the original. Each doll is a complete being on its own, but together they form an even more complex (recursive) structure.

Bonus fact: Lots of programming languages now have a limit on how many times you can recursively call a function so you don’t accidentally end up stuck in a loop 5ever

In computer science, recursion is the term for calling the same function over and over again on the same (or different) items, until a designating stopping point is reached. The key quality in both this and the Matryoshka doll example is that the target structure or item can theoretically go on forever – there is no rule intrinsic to the structure itself that says “you have to stop when X.” In fact, in computer science, recursive loops can be a big problem when you forget to include some sort of stopping criteria, because when you run your code you’ll end up essentially stuck in the same loop forever and, unlike our relatively limited working memory, computers are great at dragging out a task until the end of time (that’s why you gotta memorize the “kill switch” for your command line).

Cardinal numbers are also recursive, in that they are limited only by our own inability to pay attention and/or conceptualize something like 7,231,592,539,129,301,523 (that’s more than seven quintillion, FYI). You can make a number infinitely bigger or smaller, in theory, with the only limit being its practicality and your own attention span. Each time you do, you do so by embedding the smaller number(s) inside of a bigger number.

A good mathematical example of how recursion puts something inside itself is exponent notation, where something like 2ˆ3 differs from 2*3 in that the former takes the output of a previous operation as its input – 2^3 can be rewritten as (2*2)*2, whereas 2*3 can be rewritten as 2+2+2 (the number 2, three times). That is why the number expressed by exponent notation differs so greatly when you increase the digit in the exponent by 1: each iteration takes the output of the previous iteration as its input, i.e. it is recursive, meaning the result of the previous part of the equation forms the basis for the next part of the equation. Recursion is everywhere in math, and as it turns out, it is nearly as commonplace in language too.

In Language and Linguistics

Many different structures in language can be recursive, and this is what some linguists such as Noam Chomsky argue distinguishes the expressive capacity of human language from animal communicative systems. Language, despite a finite set of rules, can express an infinite number of ideas and combinations – same as math. A famous observation from Chomsky is that language allows you to comprehend familiar words in unfamiliar configurations; in other words, you can understand a sentence that you have never heard in your life, because you know the structures that were used to create that particular sentence. (As an aside, this general observation has led to some A+ meme material on linguist Twitter, where people love to share absurdist headlines or statements that they encounter in real life as “evidence” that grammar allows you to combine words in ways no one has ever seen or heard before – see my favorite below).

“Syntax allows you to produce and understand sentences that no one else has ever said in the history of humankind” -Linguists (Image source)

1. My mom’s friend’s wife’s sister’s boyfriend’s snake has an eye infection. (= one snake, one owner)
2. My mom’s, friend’s, wife’s, sister’s, and boyfriend’s snake has an eye infection. (= one snake, five owners)

In language, recursion is what allows us to create infinitely long sentences, by adding new information to a pre-existing structure. The sentence in (1) recursively embeds possessive phrases within one another; its meaning is not the same as sentence (2) because (1) takes the output of each possessive phrase as the input for the phrase above it (e.g. whose boyfriend? >sister’s boyfriend. Whose sister? >wife’s sister, etc), whereas (2) outputs everything all at once (whose friend? >my friend. Whose mom? >my mom, etc). So, although they have almost the exact same words in the same order, we can say that there is something different about the structures of (1) and (2).

Kids and second language learners have a really hard time with sentences like (1), and previous research has demonstrated that they will often assign it the same meaning as (2), i.e. they reject the recursive structure in favor of a conjunctive or coordinative structure. This is interesting, given Chomsky’s observation that recursion is what makes human language unique from other forms of communication. If recursion is the distinguishing factor, then why shouldn’t kids be able to use it intuitively in cases like (1)?

We know, clearly, that humans can understand recursion at an abstract level; there is evidence all around us, as I demonstrated with the Matryoshka dolls, computer science, and mathematics, all of which are manmade. So to some extent, it seems that this knowledge is part of human cognitive abilities in general. What I – along with many other linguists – am interested in is why there seems to be such a strong preference for some types of recursion in language, but not others. For instance, the Minimalist framework attributes sentence formulation to a process called Merge, which is basically the idea that you can combine one word or phrase with another, and select one of them as the “head.” Most Merge operations in English are right-headed, meaning that the item on the right becomes the head of the phrase: dog+house is a house, not a dog – but in Japanese it would be the opposite. You can perform Merge recursively to create a phrase like the blue doghouse, and then again to create a full sentence like My puppy sleeps in the blue doghouse. Kids pick up on this unbounded Merge operation by the time they are ±3 years old; however, they may still struggle to understand and produce sentences like (1) as late as age 10. There must be some reason that they take easily to some forms of recursion but not others.

However, past research has demonstrated that, with explicit coaching and exposure to different types of recursion in their language(s), children as young as 4 years old start to “get it”. Some types of recursion seem to be easier, too, which is another intriguing difference: why can some 4 year olds follow instructions like “put the alligator on top of the lion on top of the zebra on top of the panda,” but not “give a cookie to the girl’s brother’s friend’s dog”? And why do children acquiring some languages, such as Mandarin, seem to master similar recursive structures earlier (e.g. Li et al., 2020) than children acquiring a language like English?

This is something that primary school teachers may be able to help with by exposing their students to structures like this from a young age; one way is by creating riddles using various types of recursion (I like to ask kids things like “who is your mother’s father’s grandchild?”). These kinds of structures aren’t necessarily common in day-to-day speech, which may be one explanation for the huge variability in when and how kids acquire them. Maybe we could help them by building it in to the school curriculum.

Another ongoing area of investigation is the relationship between recursion in one cognitive domain, such as mathematics, might trigger recursion in another domain like language. Christoph Scheepers, for example, has demonstrated that mathematical structures can prime specific syntactic structures, and vice versa (Scheepers et al., 2011). Can the acquisition of one structure then trigger acquisition of the other? How similar do they have to be in order to influence one another? Some pilot results from Guerrero (2020) seem to suggest that the answer is yes, but far more work remains to be done. These are some of the overarching research questions regarding language and cognition in general, but especially concerning recursion.

So, that was a general overview of recursion within and outside language, and the questions that some of us have been asking with regard to its developmental pathway and the role that innate knowledge might play in its realization in child grammar. Maybe one day – if all goes according to plan – I’ll have more answers to blog about.