Live chat with developmental psychologist Liz Kirk

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Welcome to our 30th chat write-up with developmental psychologist Liz Kirk! 30 live chats, can you believe it? For those that haven’t followed this blog from the start, you can go and read previous live chats from here. But let us not diverge, as today’s write-up is extremely interesting and packed with information on child gesture, baby signing and the effect on parents.

Liz’s research focuses on the role of infant and child gesture in various linguistic, cognitive and social aspects of development. She’s also done research on baby signing. Does it help babies learn to communicate? Or does it just stress parents out? (you can find her publications on the matter here and here)

Liz has also done research on how the ‘mind-mindedness’ of mums talking to their baby affects the child’s social development (find more info here). You can read about all this in the write-up below!

Q: Can you tell us about your studies with baby sign?
Liz: I had 40 fantastic parents with young children and they volunteered to take part in a one-year study. Parents were randomly allocated to either a baby sign group or a control group. In the baby sign group, parents were taught to use baby signs and encouraged to use these frequently with their babies. The control group did not learn baby sign and so they provided a baseline which the signing babies’ development could be compared against. I visited the families in their homes five times over the year and took extensive measures of their language abilities as they developed over time. I found no difference between the groups: baby sign did not boost spoken language development (but neither did it harm it).
@Liz: Were there any other differences between the groups?
Liz: Yes. I also looked at whether using baby sign changed the way that parents interacted with their babies. I found that baby signing parents were more responsive to changes in their child’s gaze or behaviour – you could say they were more sensitive to their child’s non-verbal behaviour. But this enhanced sensitivity didn’t have an impact on the child’s language learning.

Q: I’m doing a baby sign course now with my 9 month old. We really enjoy the classes. I see that you say it did not boost spoken language, but I’m interested in whether parents were able to communicate with and understand their babies earlier using non verbal communication. Also, do you think it can reduce the frustration between babies and parents as the baby is able to communicate earlier on what their need is?
Liz: the babies did learn the baby signs and often used them before they had the corresponding words. So yes, it was an added level of communication. However, as you will know, babies are great communicators and will let you know what they want in various ways and means! I’m glad you asked the question about frustration as this is something we asked too. We wanted to know whether parents that go to baby sign classes would experience less stress in their role as parent. So we compared the parenting stress levels of parents that attended baby sign classes compared to that of parents who were attending a non-educationally focussed class. We actually found the opposite of what was expected: the baby signing parents were significantly more stressed. We do not suggest that the classes caused increased stress but that perhaps, because of the claims made by the classes (reducing stress, improving bonding, language etc) that these classes attracted parents who were more stressed to begin with. But yes, I can see that there are times when it would help to quickly know what your baby wants and many, many parents report enjoying sharing baby signs.
@Liz: It’s easy to get frustrated with a non-verbal baby though – oh my god, what do you want!? I can see that if they can tell you ‘hungry’ or ‘wet’ or whatever, it would help.

Q: You said that baby signing didn’t seem to affect children’s spoken language development. How did you measure that?
Liz: I measured the babies’ language using various measures. One measure of vocabulary asks parents to report from a checklist of words which words their child can say and which their child can understand. Another measure (called the preschool language scale) uses a play-based assessment that measures aspects of children’s language and production. I have to say I had a lot of fun spending so much time with the families. It was wonderful to have such privileged insight into the babies’ development from 8 to 20 months. It’s a period of rapid change and since I saw them a few months apart, the change was remarkable to witness!

Q: How much variation is there naturally in how many words infants know at X age? How sure can you be that your findings would pick up small differences? We have been looking into how you can tell your results are significant 🙂
Liz: There is a fair amount of variation in children’s language development. We had to ensure that the study had sufficient power to detect any effect that might be present and having enough participants is crucial for this. We also conducted additional analyses to be sure that we weren’t missing any small effects particular to certain types of individuals. With these extra analyses we found that baby boys that started the study at 8 months with the lowest language scores of our sample benefited from being in a baby sign condition.

Q: Can you talk us through how you made sure your study had sufficient power?
Liz: Sure, we conducted a power analysis which tells you the sample size that you need to obtain the desired effect size. Basically the more participants you have, the more power you have – more likely to detect an effect. Larger effect sizes are detectable in smaller samples.

Q: I’m curious about what research you want to do next. Also if there is anything parents can do to aid language development other than the things we already know, like talking to them and making sure their needs are met, reading to them and so on.
Liz: Great question. I’m really interested in how parents read the mind of the child – this is something called mind-mindedness. I’m looking at how this correlates with non-verbal behaviours, like gestures – how do parents who are high in mind-mindedness use gesture when communicating? My PhD student Lisa Wheatley has been investigating early book sharing and how this contributes to language and cognitive development. Lisa is looking at individual differences in how parents read/share books with their 12 and 18 month olds and is isolating the specific behaviours (like pointing, personalising the story etc) that have a positive impact on the infant’s interest and attention and also their language. Lots of research has already shown that reading with babies is a fantastic way to nurture their language and cognitive development – babies are never too young to enjoy books or to gain something from the interaction.
@Liz: Oooh, what has she found out? I sometimes feel guilty when I am just reading the book out, instead of talking about each page. But I can be tired and impatient at the end of the day
Liz : She’s still analysing her data I’m afraid so I’ll have to get back to you on that one! We’re hoping to follow up the babies when they are 3 to see how the measures we have at 12 and 18 months relate to their abilities at 3. I also do research on how school aged children gesture, looking at when kids are learning about new concepts how their gestures ‘leak out’ what they understand but can’t yet put into words. I have a big study planned with colleagues in Chicago and Coventry looking at kids learning how to spell and how their gestures can reveal knowledge they can’t yet articulate – signalling they are ‘ripe’ to learn and ready for a lesson!
@Liz: That’s interesting, what are you finding?
Liz: Our pilot data with kids aged 4 and 5 has shown that before kids can explain how they spelled a word (e.g. cold) their hand gestures reveal they understand the structure of the word (e.g. onset and rime patterns). Their speech is often nonsensical but their gestures make perfect sense! You asked what parents can do to aid language – just to talk! Talk to your baby and they will hoover up language 🙂 and also pay attention to what they are doing with their hands… maybe they are gesturing something they can’t yet say. Research by colleagues has found that parents translate their children’s gestures into words, thus providing labels for things in the world that the child is ready for.

Q: Do you think the theory about parental language being poor is true (the Chomsky theory about poverty of the stimulus)?
Liz: BIG last question! The question is whether infants have an innate capacity to learn language as Chomsky argued that the environment alone cannot account for the language learning that babies achieve. So it’s not the case that parental language is poor but that babies are hard-wired to learn language – I’d agree with this. Babies start to learn features of language from the womb – if babies are read the same story in the last trimester of pregnancy every day, they will recognise this when they are born. Amazing.

Q: Have you looked into multiple language children at all? Mine is learning English and Danish simultaneously.
Liz: I would really like to study baby sign in bilingual babies. It would be really interesting to know whether baby sign helps to ‘bridge the gap’ between the two languages.
@Liz: Is there anything extra that we should be doing to foster that? To be honest even my Danish husband speaks mostly English to him (almost 3). He learns most of his Danish at daycare. But suddenly seems to be blooming in Danish. The other day he pronounced the word for rye bread in Danish better than I will ever be able to say it.
Liz: I’d just say regular exposure which sounds like you are doing already!

Q:  I realise we haven’t really talked about your mind-mindedness research. Would you be able to tell us a little about that?
Liz: We measured mind-mindedness of parents when their children were 8 – 20 months. We measured this by looking at how often they commented appropriately on their child’s mental state (what they were thinking or feeling). We then followed up the children when they had started school and measured their theory of mind – their ability to read the minds of other people. We found that there was a significant positive correlation between mind-mindedness and children’s theory of mind. So the more mind-minded parents were the better their children were at mind-reading.
@Liz: How do you measure ‘mind reading?!’ Is that the ability to understand another person’s mental state, as in happy, sad, angry?
Liz: Exactly! We filmed parents and babies at home in play and then coded every utterance that the parents made and identified all comments on the child’s emotion or cognition. Each mental comment was further coded as being appropriate (parent’s comment matches the child’s behaviour) or non-attuned.
@Liz: So, that would be the parent saying, ‘It looks like you are getting frustrated with that block’ or whatever?
Liz: Yep, that’s an example of mind-mindedness – accurately reading the child’s mind from their behaviour, using words that refer to emotion or thinking.

Q: Do you think putting words to their emotion is helpful for them? That’s what we are working on now. He’s really picked up ‘sad’ but he uses it for frustrated and angry as well.
Liz: Yes, providing words to label mental experiences appears to be important in helping the child understand their own mental life and that of those around them. This explains the correlation – that having a parent that is sensitive to your thoughts, feelings and desires helps you to understand these experiences and then in turn enables you to read the behaviour and intentions of others.
Liz: Thank you for your brilliant and insightful questions. I’d love to come back another time and keep the conversation going!
@Liz: Thank you for coming and sharing your research. I’m sure we can organise another chat if you’d like!

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