Using "naturalistic dual-EEG" to measure mother-infant brain-to-brain (b2b) synchrony in socially-mediated learning

Lead Research Organisation: University of Cambridge
Department Name: Psychology

Abstract

Learning is an inherently social activity, but previous research typically only considers the learner in isolation, or when interacting with an inanimate "teacher". Our project aims to address this gap by developing new techniques to investigate how mothers' and infants' brains co-operate during language learning. Our hypothesis, based on previous research from our lab and others, is that the electrical patterns of activity in mothers' and infants' brains become synchronised when both are jointly focussed on the same object, and this inter-personal (brain-to-brain, 'b2b') synchronisation boosts infants' learning and memory for new information. This has never been addressed before because nobody has measured the electrical activity in mothers' and infants' brains at the same time. In the past, people have only looked either at mother's brains or at their child's.

Our study will examine joint attention. Joint attention is a state of shared focus between individuals that can be initiated through eye contact, speech ("look!") or gesture (pointing). Infants learn and retain information more readily when they are jointly attending to new information with their mother. We will then go on to ask: what happens in the brain during episodes of joint attention? In this study, we will simultaneously measure mothers' and infants' naturally occurring electrical brain activity using a technique known as electroencephalography (EEG).

We predict that:
1) When mothers and infants are jointly attending, their brains are also highly synchronised;
2) Stronger brain-to-brain synchronisation helps infants to learn and remember new words better;
3) Infants' brain synchronisation ability can be strengthened through specialised training;

In the first study, we will assess the relationship between joint attention, mother-infant b2b synchrony and babies' word learning. 80 pairs of English-speaking mothers and babies will take part in a word learning game while their naturally occurring electrical brain activity is measured. Mothers will be given a few novel objects and asked to play normally with their child, whilst using new names for the objects, such as "look, this is a beelooma". At the end of the play session, we will test infants to see how well they remember the new names for these objects. Based on previous research, we expect that if the child hears a new name for an object during a period where they were jointly attending to it with their mother, they will learn and remember this name better. We will then look at the patterns of electrical brain activity we recorded to see if mothers' and infants' brains are more strongly synchronised during joint attention periods. We will also look at whether the strength of this synchronisation is related to how well babies learn new names for objects.

Our first study will look at correlations between attention and synchronisation in mothers' and infants' brains. But showing a correlation between two things is not enough to show that one causes the other. In the second study, therefore, we will look at causal mechanisms. We will give a subset of infants special training in the skill of attending. These are specially-designed computer-based training tasks that have been developed by one of our researchers. After training, all infants (including both trained and untrained control groups) will take part with their mothers in the original word learning game again. We expect that the babies who received special attention training will show greater improvements in their brain synchronisation than those who did not.

If successful, this study would be the first to show that when mums and babies are jointly attending, their brains are also highly synchronised, and this supports babies' language learning. We would also be the first to show that this neural mechanism for learning can be improved through training.

Planned Impact

Our previous experience suggests that academic and public interest in our findings will be high. Journalists from the BBC and Scientific American have already approached the PI and expressed an interest in disseminating the results of our study through newspapers, popular lay scientific journals, and radio interviews. Based on the novelty of our methods, and our previous publication records, we expect the results of our research to be publishable in high-quality journals such as PNAS and Brain. Accordingly, we expect our research to have a significant impact on both the scientific community and on the general public, where the primary beneficiaries will be other academics, and families in the community, respectively.

(1) Academic beneficiaries (primarily other social science and neuroscience researchers) :
This project is methodologically-pioneering - all dual-EEG protocols and computational algorithms will be custom-built for infants. To encourage other groups to adopt the methods that we develop, our signal processing algorithms and neural synchrony metrics will be published and made freely available online for use by other research groups. We will also disseminate our findings to the scientific community through journal publications and conference presentations. Our project is also a step toward "ecological neuroimaging", such as EEG in the home or classroom. To encourage the use of naturalistic dual-EEG in other areas of social science, we will organise a conference on "Naturalistic Neuroimaging : The Brain in Social Synchrony" in June 2017 to generate interest within the academic community.

(2) Families in the community :
We aim to generate wider public interest in and knowledge about how infants learn language from their social environments, and to support parents' engagement in their children's language learning process. For the infant learner, the most important and effective language teacher is the adult caregiver. We expect our research to highlight the importance of periods of adult-infant joint focus as optimal windows for language learning. Accordingly, our outreach efforts will focus on helping parents to generate and maximise these windows of opportunity to teach language to their children.

To broadcast this message widely, we will take advantage of existing University-wide public engagement events, such as the annual Cambridge Science Festival (http://www.sciencefestival.cam.ac.uk/), to publicise the findings of our research to families and children. We also plan to reach out to parent groups to disseminate the findings of our research. For example, we will approach organisations such as the NCT (National Childbirth Trust, http://www.nct.org.uk/, the UK's largest charity for parents) to ask if they would be interested in publicising the results of our study on their website. NCT offer research-based advice for parents on all aspects of pregnancy, birth and infant care. In addition, we plan to produce a simple leaflet for parents, summarising the results of our research on joint attention and word learning in lay terms, with suggestions of activities that parents can do with their babies in order to encourage language learning. These leaflets could be given out at baby groups at local children's centres.

Finally, we will publish our research on the University of Cambridge website (PI's home page), where there will be a dedicated set of pages for parents who wish to find out more about our research, and about possible implications for their children's language learning. We will place pdf versions of the parent leaflet on this website for free download. The University of Cambridge is a high-profile website that receives a considerable traffic and public interest.

We do not expect there to be a substantial economic impact for our project as we do not intend to commercialise any of our methods or protocols. Rather, these will be available for free download on the internet.
 
Description In infants, as in adults, social context is known to influence attentional allocation during communication and learning. The sharing of attention between individuals potentiates learning, but little is understood about the interpersonal neural mechanisms that support this process of joint attention. This grant aims to test the hypothesis that the neural activity in mothers' and infants' brains becomes synchronised when both are focused on the same object (joint attention). This inter-personal neural synchrony creates a privileged state in which infants' learning and memory for new information is temporarily boosted.
First, we conducted a pilot study with adult-infant pairs to test the feasibility of using our new dual-EEG technology with infants. We assessed whether gaze, a salient cue that elicits joint attention, moderates endogenous levels of neural coupling in adult-infant speaker-listener dyads. Across two experiments, electroencephalography (EEG) was concurrently measured in 36 adult experimenter-infant dyads at left and right central electrode locations. The adult sang nursery rhymes to the infant whilst either looking directly at the infant, or with her gaze averted by 20 degrees in a video or live context. Gaze-related changes in adult-infant neural network connectivity were measured using Partial Directed Coherence (PDC), a statistical measure of causality and directional influence. Across both experiments, our results showed that bi-directional connectivity between adults and infants was indeed significantly higher during periods of Direct than Indirect gaze. Further analyses suggested that these effects were not attributable to differences in task engagement, EEG power, or basic neural processing of speech between gaze conditions. This was, to our knowledge, the first demonstration that dual-EEG technology can successfully be used to assess neural changes during adult-infant social interaction. The results of this study were published in a high-impact journal (PNAS).
Based on the positive results from this pilot study, we proceeded to conduct Study 1 of the proposed research project. Study 1 assessed correlations between joint attention, brain-to-brain synchrony and learning in infants. 90 mother-infant dyads (aged 9-15 months) participated in a series of naturalistic play and learning tasks using dual-EEG. Mother-infant synchrony was assessed by computing the oscillatory phase-locking between mothers' and infants' EEG during these tasks, as well as by assessing temporal contingencies in their gaze patterns. Consistent with previous research we found that infants' look durations toward objects were longer during Joint Play with their mothers than during Solo Play. We also found that adults' changes in visual attention tended to precede infants' changes, suggesting that changes in adults' behaviour may drive changes in infants' behaviour. Overall, our results suggest that infants spend more time attending to objects during Joint Play than Solo Play, and that these differences are most likely attributable to increased exogenous attentional scaffolding from mothers during social play. These findings were reported in an article that has recently been accepted for publication by Developmental Science. Three further journal articles are now in preparing for submission, pertaining to the relationship between parent-infant neural synchrony and infant learning and attentional behaviour. We have also shared the data obtained from Study 1 on ReShare. This dataset comprises EEG neural indices and looking data recorded concurrently from infants and their mothers during two social conditions, Joint Play and Solo Play. The dataset was submitted to ReShare on 12th March 2018 and is currently under review, to be published.
In Study 2, we assessed whether a brief intervention (involving viewing an adult speaker offering direct or averted gaze whilst singing nursery rhymes) would cause changes in baseline levels of neural synchronicity and visual attentiveness between infants and the adult. Study 2 was completed with N=16 adult-infant dyads in Dec 2017, and the data are now being analysed.
Exploitation Route We intend to make our computational algorithms and methods for assessing interpersonal brain synchrony, including analyses of motion-related EEG artifacts and graph-theoretical indices for assessing joint-brain networks, fully-available for others' use and replication.
Sectors Digital/Communication/Information Technologies (including Software),Education,Pharmaceuticals and Medical Biotechnology,Other

URL http://www.pnas.org/content/early/2017/11/27/1702493114
 
Description Our specific findings in relation to gaze moderation of adult-infant neural synchrony have been reported internationally by over 40+media outlets, including The Telegraph, The Washington Post, MSN, Reuters TV, Canadian Broadcasting Corporation, and others. Additionally, the research arising from this project will be featured in a new documentary on infant development that is currently in production, to be released in 2019 on a high-visibility platform to an international audience.
First Year Of Impact 2017
Sector Education,Electronics,Other
Impact Types Societal

 
Title EEG Motion Artifact Library (Adult + Infant) 
Description Neuroimaging research with social interactive paradigms is challenging because of the motion artifacts that are produced by participants during interaction. There currently exists little/poor documentation of the effect of these artifacts on the measured EEG of infants (although there is existing literature on adult motion artifacts). To fill this gap, we documented the relative prevalence of 30+ different types of motion artifacts in infants and adults during social interaction, and the modelled the effects of these motions on infants' and adults' EEG signal. These results are summarised in a publication that is now under review. 
Type Of Material Model of mechanisms or symptoms - human 
Year Produced 2017 
Provided To Others? Yes  
Impact No impact yet as article has not yet been published 
URL https://www.biorxiv.org/content/early/2017/10/19/206029
 
Title Dual EEG and Looking Data (Joint and Solo Play) 
Description This dataset on ReShare comprises EEG neural indices and looking data recorded concurrently from N=42 infants and their mothers during one of two social conditions, Joint Play and Solo Play. Exact descriptions of the participants and experimental procedures are given in the manuscript, Wass et al. (in press, Developmental Science).The dataset was submitted to ReShare on 12th March 2018 and is currently under review, to be published. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact As the data has just been uploaded, there is no notable impact as yet 
 
Description BBC News Report 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact The BBC News featured a news report on the infant language learning work being conducted by Dr Victoria Leong and her research group. This report was broadcast nationally on the 6 o'clock news in Nov 2016, and an online article was published on the BBC website, which is internationally-accessible.
Year(s) Of Engagement Activity 2015,2016
URL http://www.bbc.co.uk/news/science-environment-38002105
 
Description Interview for international news agencies 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact There was widespread media coverage on our PNAS publication "Speaker gaze changes information coupling between infant and adult brains." This included coverage from over 40 international news agencies including The Telegraph, The Washington Post, MSN, Reuters TV, Canadian Broadcasting Corporation, and others. The article reached an Altmetric score of 543, which was ranked in the top 5% of all research outputs scored by Altmetric.
Year(s) Of Engagement Activity 2013,2017
URL https://pnas.altmetric.com/details/29594965
 
Description RSM Conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Dr Leong was an invited keynote speaker at the Royal Society of Medicine conference on "Enabling 21st century parents: understanding family and community relationships", where she presented her latest research findings on mother-infant synchrony and learning. Over 100 individuals (including parents and practitioners) attended the event and reported increased interest and awareness.
Year(s) Of Engagement Activity 2013,2017
 
Description Speaker at National Literacy Trust Conference 2018 (Talk To Your Baby) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact I presented the research findings from this project at the annual "Talk To Your Baby" conference of the National Literacy Trust. This conference was attended by members of the public as well as practitioners, and presented the latest research on language development as well as evidence-based practice. My work was also presented in a blog featured in Teachwire prior to the conference : https://www.teachwire.net/news/how-eye-contact-helps-babies-learn-language
Year(s) Of Engagement Activity 2008,2018
URL https://literacytrust.org.uk/early-years/talk-your-baby-conference/