If you watched the Academy Award winning film, CODA (trailer below), you’ll appreciate that the character who played the son is a native signer. That is, he learned sign language from his parents from the start.

How do we learn spatial relations? It’s a fundamental ability we pick up early. Much of what we know about how we develop spatial language, for example, left and right, and its link to spatial memory, is from studies with children exposed to language immediately after birth. A group of people, however, are not exposed to language from the get-go. These people are deaf with hearing parents who do not know sign language. Often, they don’t learn language until later and are referred to as “late signers.” About 5% are born to deaf parents and exposed to language after birth. These people are referred to as “native signers.”

Dilay Karadöller, Beyza Sümer, Ercenur Ünal, and Aslı Özyürek (pictured below), the authors of the featured article, used this difference to measure the links between spatial language use and spatial memory accuracy in ways that couldn’t be measured in typically developing children. In this podcast episode, I speak with Dilay about their research.

Transcription

Intro

Chung: You’re listening to All Things Cognition, a Psychonomic Society podcast. Now, here is your host, Laura Mickes.

Intro to the interview with Dilay Karadöller

Mickes: In the upcoming interview, I speak with Dilay Karadöller about her paper published in the Psychonomic Society journal, Memory & Cognition.

Interview with Dilay Karadöller

Mickes: Thank you so much for interviewing with me about your paper.

Karadöller: Yeah. Thank you for the invitation.

Mickes: Your paper is called “Late sign language exposure does not modulate the relation between spatial language and spatial memory in deaf children and adults.” And it’s published in Memory & Cognition. If you allow me, I’m gonna try to sum it up and you tell me if I got it or not.

So, in a nutshell, the paper describes research that you and your collaborators conducted where you’re interested in … if deaf children and adults who use sign language have similar associations between spatial language and spatial memory, that’s found typically in hearing children. So you wanted to see if you found that. Importantly, some of your participants learned signing very early, I believe you call it “native.”

Karadöller: Yeah.

Mickes: Some learned signing later. Did I get the gist of it?

Karadöller: Yeah, kind of. [laughs]

Mickes: [laughs] Will you please give us some background to the research?

Karadöller: Yeah, sure. Of course. We are chasing after one of the fundamental abilities that children need to develop, which is communicating and reasoning about spatial relations. I’m sure you can relate that children from very early on observe and manipulate on objects around them. These objects are often configured in various spatial relations to each other, such as when they’re eating on a table, there’s a fork left of the plate for instance, and they somehow figure out communicating about these spatial configurations and remembering them later on maybe for certain processes.

However, when we look at the literature, majority of previous studies, who aim to understand the development of communication and reasoning of spatial relations, they draw on data from children growing up with typical linguistic experience. So these children are exposed to a language right after birth.

Mickes: Right?

Karadöller: Unfortunately, this is not the case for many deaf children. Most deaf children, like around 95% of the deaf population, are born to hearing parents.

Mickes: Wow!

Karadöller: And they lack immediate access to a conventional sign or spoken language. They cannot access to the spoken language around them because they cannot hear. And usually their parents are hearing, who doesn’t know sign language, so they cannot communicate with their kid in sign language. And even with hearing aids, these devices may not provide enough access to the surrounding speech in some circumstances.

Mickes: They may not be picking up the spatial language …

Karadöller: Any language, not only spoken language

Mickes: Of course, but …

Karadöller: They cannot pick up any language

Mickes: 95%!

Karadöller: Yeah, it’s a huge percentage.

Mickes: Wow.

Karadöller: These children are called “late signers” because they get their first exposure to a conventional language usually later in life. For instance, in our case, in our data, is that children were getting their sign language exposure around the age six when they start the school for the deaf.

Mickes: Wow.

Karadöller:

And the mean of education was not also in Turkish sign language. It was a Turkish sample. They only get exposed to sign language – the first sign language exposure they had is from peers who know sign language only during play sessions or recess.

Mickes: Oh. Are the parents using gesture?

Karadöller: Sure. There are gestural communication systems at home, but these are idiosyncratic.

Mickes: Sure.

Karadöller: Every home situation has a different communication system. There might be of course, similarities. Some research also suggests, but generally these home signing, they call, situations are specific to this particular household and they don’t very much resemble like conventional language system. So these kids needs a exposure to a conventional sign language.

Mickes: Does this affect your … I’m jumping way ahead, but do you worry that this home signing affects the results that it makes your late signers, more, more, uh, variable?

Karadöller: Things are of course more variable. There could be effects of those that we couldn’t control.

What we could do to control some of these effects is to control for the duration of sign language exposure. All of the late signing children in our sample in the paper had been exposed to sign language for two years at the school situation.

Mickes: Okay.

Karadöller: So all of these children in our sample were exposed to sign language at school and for two years long.

Mickes: Okay. So that’s the, the tight control you had over it.

Karadöller: So, that’s the only control that we had, but we don’t know what happened to them in their home signing situations. Another percent of the deaf population, the 5% of the deaf population have deaf parents and we call them “native signers” in the paper, as they are exposed to sign language from birth onwards, from their deaf parents and caregivers. So, like typically developing hearing children that we talk about at the beginning, they have immediate language exposure, which is a conventional language. The only difference is the modality.

Mickes: Right.

Karadöller: Yeah. So in our work, what we did is that we investigated such atypical cases of language acquisition, like late signers in comparison to a typical acquisition case in the same modality. We think that it can shed light and give some insights into the complex interplay between spatial language use and spatial memory accuracy, like in ways that may not be possible by studying, of course, typically developing children. So it’s kind of very exciting.

Mickes: That is exciting. The exact research question, is what?

Karadöller: The exact research question is:  Do timing of language exposure influences, first, the way signers encode spatial relations in sign language. I mean, spatial relations between objects, of course, and, and whether the timing of sign language exposure, as well as the variations in the way they encode spatial relations between objects due to these exposure differences, predict memory for spatial relations.

Mickes: Okay. Got it. And how did you test it?

Karadöller: We had a design where we had a participant and an addressee. We designed a display with four pictures. In every picture, there were like two objects, apple, and a pencil, for instance. One of the objects was more bigger and the other one was more smaller in size, maybe like plate than a fork, let’s say.

Mickes: Okay.

Karadöller: And then the bigger object that we named “ground object” was always in the center of these four pictures. So imagine like two by two grid display with four pictures in every of the picture, there’s a plate in the middle. And what we did in this four picture is that we varied the spatial configuration of the fork in relation to the ground. Sometimes the fork was to the left of the plate. Sometimes it’s on the plate, like under the plate or something like that.

Mickes: Okay.

Karadöller: So there was one arrow appearing in the middle of the screen, uh, targeting one of the pictures and we tell participants to describe the target picture that is pointed with an arrow to the addressee in front of them. They like describe 84 displays like that in various spatial configurations. And then they did a distractor task and then they got a surprise memory task.

And in this memory task, what happened is that they received the similar displays with same pictures, but we removed the arrow and randomized the order of the pictures in the display. And we asked them which one of the pictures that you had described to the addressee previously,

Mickes: Okay,

Karadöller: This was the memory component.

Mickes: Right. Before the memory test, they would sign what they saw.

Karadöller: Yeah.

Mickes: Could you give an example of it?

Karadöller: Yeah. Well, what usually what happens is that there are several ways in sign languages that you can, uh, express the spatial relation between objects. And one of the conventional linguistic forms is called “classifier constructions.” I will sign how they look for you. In this constructions what happens is that they, uh, depict the picture through their hands. They first introduce the lexical sign, for instance, this is a lexical sign for plate. And this is a lexical sign for fork in Turkish sign language. So we know have the reference, like object, but we don’t know the spatial relation between them. Right?

[videopress wTVESttu]

Mickes: Yeah.

Karadöller: And then they choose certain hand shapes to represent the size and shape properties of these hand shapes. And they put their hands on the signing space in front of them and configure the spatial relationship. For a plate, for instance, they might have like half round hand shape like that.

[videopress AUlc6gek]

Mickes: Right.

Karadöller: They put it in the middle and for fork, they chose usually an elongated hand shape, for instance, and put it next to the plate in an analog way that is depicted in the original target picture.

Mickes: Right. So that’s how they then describe it. And then you have the surprise memory test. Yeah. And, and this was in the native signers and then the late signers.

Karadöller: Yeah.

Mickes: Okay. Is there anything else they did?

Karadöller: There are alternative ways to do it. For instance, they might use lexical terms like left, right. To indicate the locations of objects or they can point to the location of the object. The most complex way to depict actually is through classifier constructions.

There are many linguistic forms, linguistic constructs. Let’s say that you have to choose the correct hand shapes, use your hands simultaneously and so on and so forth. So what we predicted … also we found in an early research is that classifier constructions are hard to be learned. So it’s a late aspect of linguistic development and late signers, although they seem so iconically motivated, have a hard time to do it. They use classifier constructions less frequently than their native signing counterparts, even in adulthood.

Mickes: Wow. Are they ever able to pick it up?

Karadöller: Yeah, they do. Of course they, they

Mickes: Not naturally.

Karadöller: There’s no signer who doesn’t do classifier construction, but they tend to use classifier constructions less compared to other simpler forms, simpler one being, for instance, pointing, you don’t have to think about the hand shape configuration so much. You can just point that the fork is here, for instance,

Mickes: Right. Easier.

Karadöller: Yeah. Easier, more easier compared to others. Yeah.

Mickes: What did you hypothesize?

Karadöller: So we first predict that the timing of sign language exposure that like being a late signer or native signer will influence the way signers encode space. There might be differences in the way they choose certain linguistic structures to encode the spatial relations between objects. We also somewhat documented it in our earlier study published last year.

And for the relationship between spatial language use and spatial memory accuracy, we, we had alternative predictions actually because we were testing what we will find. We thought that late exposure or timing of sign language exposure may influence the memory for spatial relations by itself, possibly due to shorter experience with a conventional language.

Mickes: Right.

Karadöller: Also we thought that the ways in which signers encode space might also predict differences in spatial memory. For instance, iconically depicting a spatial configuration may predict a higher memory accuracy than depicting it less iconically. For instance, because iconic depictions might create more action representation or they might create double encoding and more memory traces in their mind during description that may lead to better memory accuracy in the surprise memory, task.

Mickes: This was my question. This is what I was going to ask you later. Okay. Good [indistinguishable]

Karadöller: Alternatively,

Mickes: Yeah.

Karadöller: It is also possible that neither this timing of sign language exposure, or nor the ways in which signers encode the spatial relations predict spatial memory. And this could mean that the relationship between spatial language use and spatial memory are either nuanced or that the two systems are governed maybe independent from each other.

Mickes: Those are your predictions.

Karadöller: Yeah. Those, those were our predictions.

Mickes: And were they supported?

Karadöller: Partially, yes. We found that timing of sign language exposure indeed influenced the ways in which signers encode space. However, neither the timing of sign language exposure nor the variations in the ways in which signers encode spatial relations predicted spatial memory.

Mickes: It did?

Karadöller: No, it didn’t.

Mickes: It did not predict spatial memory?

Karadöller: No, it didn’t. Yeah. It did not predict spatial memory. Yeah.

Mickes: Really?

Karadöller: Yeah.

Mickes: I’m surprised by that.

Karadöller: Yeah. We too, but we were somewhat, somewhat expecting it as well. And uh, yeah. Also, it’s something nice to find, right? So, if you are even delayed in like acquiring sign language, it seems that, at least, even though you are using different linguistic structures to encode or communicate about spatial configurations between objects, but it does not affect your memory for spatial relations in our particular task.

Mickes: What do you think it all means?

Karadöller: Oh [sigh] …

Mickes: It’s a big question.

Karadöller: Yeah. It’s a big question. At least what I can say that the results that we presented in this work shows that being exposed to sign language late, of course, in comparison to being exposed to early, influences the ways in which we look at both the frequency and type of different spatial linguistic forms in encoding left-right relations.

Because I haven’t mentioned in previously, but we were interested in left-right as a particular domain. Left-right spatial configuration between objects, which is found to be cognitively also linguistically a late aspect of spatial domain. It is the one that is learned later than for the “in,” “on,” or “from behind.”

Mickes: Oh.

Karadöller: Early versus late exposure to sign language, does not necessarily predict further variations in memory accuracy, at least within our task.

Mickes: What are you going to do next? Are you following up on any of this work?

Karadöller: Yeah, we are following up on it. We already have data and are analyzing data for visual attention patterns of participants during a planning of description. So it’s possible that effects of language on cognition are not salient if the task, such as the memory experiment in our case, carried out after the language use was completed.

Mickes: Oh.

Karadöller: Yeah. Through an eye tracking experiment, we will search whether the relationship between language and cognition, spatial language uses and spatial cognition is visible during an online task, like during or immediately prior to language is being used.

Mickes: Ohhhh.

Karadöller: We already documented participants’ eye tracking patterns. Where do they look on the display while planning a description. And now, we will link these patterns to their types of linguistic forms they use and the frequency of them, compared across late and native signers.

Mickes: Can you tell me what you found or no? You’ll wait

Karadöller: Oh no, we haven’t. Oh yeah. We haven’t reached… [laugh]

Mickes: This is the ultimate cliff hanger. [laugh]

Karadöller: Yeah.

Mickes: Okay. So we’ll, we’ll just have to wait and see what you found.

Karadöller: We were interested in the domain of left-right relations between objects. Because across many spoken languages, it has been documented that left-right is a late aspect of spatial language development. And around age eight, speaking kids cannot use left-right spatial terms to talk about left-right spatial relations between the objects.

But, research shows that, from one of our collaborators, Beyza Sümer, research shows that signing kids can encode left-right spatial relations between objects earlier in sign compared to speaking kids in speech because they can iconically encode it.

What they have to do is they have to learn about abstract concepts of left and right, which are symmetrically similar, and map different spatial terms. Like this side is my right, and this side is left, or this side of the object is right, and this side of the object is left. Although these sides are symmetrically similar. So this abstract mapping of spatial terms to the concepts are maybe hard for speaking kids and easy for signing kids.

Mickes: That makes a lot of sense that they have a better understanding of it because they’re,

Karadöller: yeah

Mickes: … they’re using space.

Karadöller: Yeah.

Mickes: To talk about space.

It’s so neat. Yeah. There’s a mnemonic to hold your hand up and that makes an L shape and that’s the left.

Karadöller: Yeah.

Mickes: I think I used that thing for a long time. [sheepish laugh]

Karadöller: You also did some body-anchored queing to remind you yourself for your own left-right?

Mickes: I did?

Karadöller: Yeah.

Mickes: Aargh!

Karadöller: [laughs] Yeah.

Mickes: You didn’t test any hearing children or adults.

Karadöller: Actually, we also have data from hearing participants that we presented in an earlier study. And it is interesting though, that we found hearing children around the same age as age eight are using left-right spatial terms in Turkish, less frequently than their adult counterparts. They are relying more on their gestures to complement the missing information in their speech. So, they do also use some body representation. So, they use gestures to communicate about left-right spatial relations between objects.

Mickes: So, they are actually “signing” it in an unofficial way.

Karadöller: Laughs.

Mickes: Okay. [Laughs] You would never call it signing.

Karadöller: I would never call it signing.

Yeah. They are using their gestures to complement the missing information in their speech.

Mickes: I just assumed that they [def children and adults] would be better at spatial … everything because of their embodied language. That is the case of some of your other research.

Karadöller: Yup.

Mickes: Thank you so much for talking to me about your research.

Karadöller: Thank you for the invitation. It was very nice to chat with you about the research.

Concluding statement

Chung: Thank you for listening to All Things Cognition, a Psychonomic Society podcast. If you liked this episode, don’t forget to follow the channel using your favorite podcast player or app.

All members of the Psychonomic Society receive free access to our seven journals and are invited to attend our annual conference at no charge. Learn more and become a member by visiting us online at www.psychonomic.org.

Featured Psychonomic Society article

Karadöller, D.Z., Sümer, B., Ünal, E., &  Özyürek, A. (2022). Late sign language exposure does not modulate the relation between spatial language and spatial memory in deaf children and adults. Memory & Cognition. https://doi.org/10.3758/s13421-022-01281-7