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


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 (, 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,, 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.


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publication icon
Leong V (2017) Speaker gaze increases information coupling between infant and adult brains. in Proceedings of the National Academy of Sciences of the United States of America

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 19 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. Electroencephalography (EEG) was concurrently measured in 19 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. Gaze-related changes in adult-infant neural network connectivity were measured using Partial Directed Coherence (PDC), a statistical measure of causality and directional influence. Our results showed that bi-directional connectivity between adults and infants was indeed significantly higher during periods of Direct than Indirect gaze in Theta, Alpha and Beta EEG bands. 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. Further, in Alpha and Beta bands, but not other bands, infants influenced adults more strongly than vice versa. This is the first demonstration that dual-EEG technology can successfully be used to assess neural changes during adult-infant social interaction. Our pilot results also demonstrated that mutual direct gaze (which potentiates joint attention) increases adult-infant neural coupling during social communication.

Based on the positive results from this feasibility pilot, 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. 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. The strength of mother-infant synchrony was contrasted during periods where they were jointly attending to an object and periods where they were attending separately to that object. We predicted that mother-infant synchrony would increase during periods of joint attention, and that both the strength and duration of brain synchrony would predict individual infants' success in learning. On 1 March 2017, Study 1 was completed with 80 pairs of mothers and infants as participants. Data analysis of these results is now on-going.

Study 2, which will assess the causal relationship between brain synchrony and attention using a training paradigm, is now being prepared.
Exploitation Route We intend to make our computational algorithms for assessing interpersonal brain synchrony fully-available for others' use and replication.
Sectors Digital/Communication/Information Technologies (including Software),Education,Pharmaceuticals and Medical Biotechnology,Other

Description Our pilot findings have been reported nationally by the BBC on television, as well as in an online news report.
First Year Of Impact 2016
Sector Education,Electronics,Other
Impact Types Societal

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
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