How you become you: The story and science of early childhood

Author: Prof. Eamon McCrory, University College London, Anna Freud Centre

Professor Eamon McCrory, member of The Royal Foundation Centre for Early Childhood Advisory Group, explains the science behind Layla’s Story and the importance of relationships in our early childhood.

While our memories may fade, decades of longitudinal research show that our early years play a critical role in shaping our lives as adults (1,2,3). Our experiences as a baby, infant and young child draw the plot lines of our life story, influencing our physical and mental health, and the relationships we form as adults. These relationships are key to a healthy society. They lay the foundations for our collective capacity to learn, to be productive, to co-operate and to thrive as a species. This is because humans are quintessentially social animals. 

How does this happen? In this short film we follow Layla. Like all of us, she is born vulnerable and entirely dependent on others. We see with beautiful simplicity how her capacities and her identity emerge through the intricate and iterative dance of human interaction. We see the profound influence of parents, carers, grandparents, friends, early years workers and neighbours. How their attention, tenderness and curiosity act as both a catalyst and support for her social, emotional, physical and cognitive development. 

The science of child development has begun to reveal the inner workings of this remarkable process. How, during our early years, we are forged by social connection. Understanding this period of our lives sheds light on what it is to be human. It provides us with clues to an enduring puzzle.

What shapes who we become? 

The developing brain

A good place to start is the brain. Most people typically think of the brain in terms of biology - a complex set of neural connections and neurotransmitters. This of course is true.  However, a purely biological perspective does not tell us what our brains are for

Unlike other animals, humans have succeeded as a species not because we are good at getting what we need from the physical world. Rather, we have succeeded because of our capacity to build and maintain a social world. This remarkable human invention acts as a vehicle for shared culture and knowledge to evolve and to be transmitted from one generation to the next. The evolution of our species has been driven by this capacity (and need) to be social. For us, like for Layla, this drive starts right from birth. 

When she is born, Layla’s brain is, quite literally, made up of billions of neurons. These first undergo a rapid process of forming connections – or synapses – and then a process where some of these connections are pruned away. This sculpting shapes the brain at an extraordinary pace (4). 

When we see Layla as a baby it is hard to imagine that she is forming as many as one million synapses or connections per second. By the time we see her running into the arms of her mum, her brain is already more than half the weight of an adult’s. And by the time she has her first slice of birthday cake aged 5 her brain is already 90% of adult size (5). This tells us something very important: that the early years are a period of intense brain development. During this time our neural connections are shaped by our genes and our environment – including our social connections. These social connections are to our brain what oxygen is to our lungs. They feed the development of our sensory and motor systems, our language and cognitive skills and determine the direction we take as we begin our journey in life. In doing so, they help shape who we become as adults.  

Longitudinal studies have shown that our cognitive and emotional functioning at age 3 is robustly associated with our mental health, physical health and social outcomes by the time we reach middle-age (1,2). Genes (which we cannot change) are of course a key influence. But it is our environmental and social context (which we can change) that unleashes or restricts our unique genetic potential. To kick-start the process, we are born with an extraordinary mechanism that ensures we (and our brains) can tap into the most abundant source of new information about the world: other humans. 

The attachment system

Human infants are born utterly dependent on their caregivers, which makes us extremely vulnerable. This means babies have strong feelings of being loved and cared for, but also of being frightened, cold, hungry, upset, and lost. We very quickly need to become important enough to those around us if we are to survive. This is where our attachment system comes in. Evolution has ensured that we all have an innate instinct for social connection, seen in the baby’s immediate preference for human faces (6). Indeed, even in the womb, Layla is learning the sound of the voices around her.

As a baby when she is nestled with her parents, Layla learns quickly who her primary attachment figures are. Invisible but powerful and long-lasting emotional bonds are forming in the neural and hormonal architecture of the attachment systems of Layla and her parents (7). This allows for connection and repair in the many interactions that unfold each day as Layla is fed, changed, sung to and hugged. 

One reason parenting can be so exhausting is because the attachment system is not there simply to meet a set of physical needs. Babies also co-opt the capacities of our emotional system (7). This primes parental sensitivity, so that caregivers are attentive and responsive to the infant’s signals and needs. This enables them to become an emotional base – providing a sense of security, that the world is safe and (largely) predictable (8). In doing so, Layla is able to begin to learn about herself, to take risks and explore, and discover what is important to learn about in her environment. This sets the template or model for future relationships and contributes to a capacity to trust others. We see this as Layla starts school. With feelings of being scared and alone she leaves her mum, needing to establish an entirely new set of relationships. In doing so she is guided by the internal models shaped by her early attachment experiences. 

In the early years it is easy for new parents to worry that they are getting things wrong. Luckily, our attachment system is not designed for perfection. If it was, humans would not have survived long as a species. While extreme experiences of abuse or neglect can have long lasting consequences for cognitive, emotional and social functioning, including disorganised patterns of attachment, infants are pretty robust to a range of more ordinary parenting experiences (9). However, we know that the mental and physical wellbeing of parents are key to their capacity to provide a secure base for their child. Experiences of depression, isolation and high levels of stress mean that parents can struggle to care for their family (10). This is why it is so important that we create a world that reduces stress for new families and ensure they have access to the practical and emotional support they need (10). 

A system of minds 

As John Bowlby, the father of attachment observed in 1951, “If a community values its children it must cherish their parents” (11). Layla’s Story shows that her successful development is in fact the result of an extraordinary collaboration among many actors. We learn, for example, that Layla’s parents are struggling because of lack of sleep – one of a range of common stressors and challenges faced by new parents. We hear an offer of support and help, perhaps from a friend or grandparent. This care and attention from others helps anchor a parent’s own ability to provide care and attention. Again, this is not just about physical needs. It is about how human social connection depends on the connection between minds. Our thoughts, feelings and desires matter. When carers are supported, they are better able to be curious, interested and nurture the mind that is beginning to blossom under their care. 

This process, called mentalisation, helps us learn about the infant (12). Are they hungry or tired? Do they prefer giraffe or teddy? Would they rather be sung to or tickled? In other words, Who is this new little person? Who is Layla? We see that Layla’s parents are open to learning who she is, saying “You’ve been very chatty today! … Are you going to catch me?”. Like her parents, we see that Layla’s nursery assistant also shows interest in her mind and her feelings as she starts at school on her own. 

Early years workers and parents alike take this approach because they know that no two children are the same. Temperament and personality are part of our individual genetic blueprint that in turn shape how others respond to us. This is true for Layla like for all children. By being curious, the adults around her discover who Layla is as she shows her preferences and interests, her likes and dislikes. Sometimes parents will get things wrong. This is okay. The naturally imperfect process of getting to know another mind helps Layla develop her own mind, and her sense of self. Even before she can speak Layla begins to be sensitive to others through early turn-taking, following another person’s gaze and even making social evaluations. By age 3 or 4 this has matured into the capacity for a ‘theory of mind’ allowing her to understand that others have thoughts, feelings and intentions that can be different from her own (13,14). Her own ability to mentalise is a key step in her capacity to build relationships with others, including with her peers. 

Building relationships

Like all humans, Layla needs to build relationships with others beyond her immediate caregivers. We see her playing football on her first days at school, fighting over a teddy and then, in a moving sequence, recognising the distress of another child. As a little boy drops his ice-cream Layla spontaneously moves forward to offer her own. At this point we see her mentalising abilities in action – she can imagine what that little boy is thinking. More than this, we see her emerging capacity to empathise and show altruism – to feel the emotional pain of another and comfort them. Even by preschool young children will have developed sophisticated capacities to gauge what is right and wrong in the behaviour of their peers – even if there is no adult present (15). These are the first steps towards making more mature moral judgements and acting in ways that benefit others. Being able to mentalise is an important part of this, but so too is the ability to regulate our emotions. 

When Layla is fighting for a teddy with another child she may know that it is not hers, but she cannot help herself. She is still struggling with a limited capacity for self-control – something that needs to be supported and nurtured by the adults around her. Self-control turns out to be essential to our capacity to establish adaptive social relations with others, and has long term impacts on our mental health (16). Any of us managing challenging relationships at work or at home will know intuitively how true this is. 

By showing sensitivity and warmth, modelling effective emotion regulation themselves and creating a nurturing environment, adults help build the foundations for a child’s self-control (17). This helps them begin to share and co-operate with others, even when that feels hard. These prosocial responses and behaviours, supported by a secure attachment to parents, develop in complexity and sophistication across childhood. They are essential in helping form bonds with other children – bonds that will in time transform into friendships and wider social networks, that in turn will provide emotional and practical support, and opportunities to learn and grow. 

Mastery and learning

Alongside social and emotional development our brain during the early years is also learning to master the abstract and the physical: there are rapid advances in language and numeracy and in motor co-ordination. In the animation, we hear Layla utter her first words as she plays with her blocks, scaffolded by her dad’s encouragement and emotional support. Her brain, of course, will have already been acquiring the sounds of words as well as their meaning as she listens and observes the adults around her. We know that young children can understand much more than they can speak (18). The more successfully an infant acquires language the better her later reading and school performance will be (19) and the better their relationships with their peers (20). We know that young children with poor language skills are at greater risk of psychosocial and emotional adjustment problems, and are more than twice as likely to be unemployed in their mid-thirties than their peers (21). 

Many factors influence how successfully and quickly we acquire language in our early years – including the genes we inherit and the socio-economic context into which we are born. But once again, the quality and richness of parental interactions is key. Language stimulation at home, like when we hear Layla’s grandparents singing a nursery rhyme to her as a baby, or the playing of word games and reading books, predict future language outcomes (22). Similarly, knowledge of numbers, developing the ability to count, and grasping that some groups of things are bigger than others are all influenced by how parents interact with their child (23). Like with language, early numeracy skills are an important foundation for future academic achievement (24). Of course, learning is more than numbers and letters. We see Layla learning to walk and run, to kick a ball and take a deep breath as she plunges into the swimming pool on her own for the first time. This learning is vital in forging our sense of agency and mastery – a confidence that we carry into adulthood – that we can meet and overcome the challenges we face in life. 


We have seen how, during the first few years of life, the quality of human connection underpins almost every part of our development. Besides our genes, our relationships with others play the signal role in shaping our future social, emotional and cognitive capacities. We see this in Layla’s story. By the end of the animation she is enjoying her fifth birthday, ready to embark on the next stage of life. Her journey and that of her parents was shaped by relationships that provided emotional and practical support. Relationships that created a sense of being cared for, thought about, understood - and loved. 

Layla’s Story is just one among many: we all have our own story. Not everyone has been as lucky as Layla. This matters because the stories of early childhood collectively shape the society we will inherit. By fundamentally rethinking how we prioritise and invest in the early years – by recognising the powerful relational forces that shape each of us as humans – we can write a new ending. An ending where mental and physical health outcomes are transformed. Where we prioritise prevention rather than cure. And where every child, like Layla, is given the opportunity to build strong foundations – and reach their full potential. 


  1. Richmond-Rakerd, L. S., D’Souza, S., Milne, B. J., Caspi, A., & Moffitt, T. E. (2021). Longitudinal associations of mental disorders with physical diseases and mortality among 2.3 million New Zealand citizens. JAMA network open, 4(1), e2033448-e2033448.

  2. Caspi, A., Houts, R. M., Ambler, A., Danese, A., Elliott, M. L., Hariri, A., ... & Moffitt, T. E. (2020). Longitudinal assessment of mental health disorders and comorbidities across 4 decades among participants in the Dunedin birth cohort study. JAMA network open, 3(4), e203221-e203221.

  3. Richmond-Rakerd, L. S., D’Souza, S., Andersen, S. H., Hogan, S., Houts, R. M., Poulton, R., ... & Moffitt, T. E. (2020). Clustering of health, crime and social-welfare inequality in 4 million citizens from two nations. Nature Human Behaviour, 4(3), 255-264.

  4. The Center on the Developing Child at Harvard University. Brain Architecture. https://developingchild.harvard.edu/science/key-concepts/brain-architecture/

  5. Lenroot, R.K. & Giedd, J.N. (2006). Brain development in children and adolescents: insights from anatomical magnetic resonance imaging. Neuroscience & Biobehavioral Reviews, 30(6), 718-729.

  6. Johnson, M. H., Dziurawiec, S., Ellis, H., & Morton, J. (1991). Newborns’ preferential tracking of face-like stimuli and its subsequent decline. Cognition, 40, 1–19.

  7. Feldman, R. (2017). The neurobiology of human attachments. Trends in Cognitive Sciences, 21(2), 80-99.

  8. De Wolff, M. S., & Van Ijzendoorn, M. H. (1997). Sensitivity and attachment: A meta‐analysis on parental antecedents of infant attachment. Child Development, 68(4), 571-591.

  9. Zeanah, C. H., & Gleason, M. M. (2015). Annual research review: Attachment disorders in early childhood–clinical presentation, causes, correlates, and treatment. Journal of Child Psychology and Psychiatry, 56(3), 207-222.

  10. Madigan, S., Oatley, H., Racine, N., Fearon, R. P., Schumacher, L., Akbari, E., ... & Tarabulsy, G. M. (2018). A meta-analysis of maternal prenatal depression and anxiety on child socioemotional development. Journal of the American Academy of Child & Adolescent Psychiatry, 57(9), 645-657.

  11. Bowlby, J. (1951). Maternal care and mental health. World Health Organisation Monograph. Serial No. 2. P.84.

  12. Fonagy P., Gergely G., Jurist E. L., Target M. (2002). Affect regulation, mentalization, and the development of self. New York, NY: Other Press.

  13. Baron-Cohen, S., Leslie, A. M., & Frith, U. (1985). Does the autistic child have a “theory of mind”? Cognition, 21(1), 37-46.

  14. Leslie, A. M., Friedman, O., & German, T. P. (2004). Core mechanisms in ‘theory of mind’. Trends in Cognitive Sciences, 8(12), 528-533.

  15. Smetana, J. G., Rote, W. M., Jambon, M., Tasopoulos-Chan, M., Villalobos, M., & Comer, J. (2012). Developmental changes and individual differences in young children’s moral judgments. Child Development, 83(2), 683–696.

  16. Moffitt, T. E., Arseneault, L., Belsky, D., Dickson, N., Hancox, R. J., Harrington, H., ... & Caspi, A. (2011). A gradient of childhood self-control predicts health, wealth, and public safety. Proceedings of the national Academy of Sciences, 108(7), 2693-2698.

  17. Cooke, J. E., Kochendorfer, L. B., Stuart-Parrigon, K. L., Koehn, A. J., & Kerns, K. A. (2019). Parent–child attachment and children’s experience and regulation of emotion: A meta-analytic review. Emotion, 19(6), 1103.

  18. Pinker, S. (1994). The language instinct: How the mind creates language. New York: Morrow and Co.

  19. Pace, A., Alper, R., Burchinal, M. R., Golinkoff, R. M., & Hirsh-Pasek, K. (2019). Measuring success: Within and cross-domain predictors of academic and social trajectories in elementary school. Early Childhood Research Quarterly, 46, 112-125.

  20. Evans MA. Reticent primary grade children and their more talkative peers: Verbal, nonverbal, and self concept characteristics. Journal of Educational Psychology 1996;88(4):739-749.

  21. Law, J., Rush, R., Schoon, I., & Parsons, S. (2009). Modeling developmental language difficulties from school entry into adulthood: literacy, mental health, and employment outcomes. Journal of Speech Language and Hearing Research, 52(6):1401-16.

  22. Farrant, B. M., & Zubrick, S. R. (2012). Early vocabulary development: The importance of joint attention and parent-child book reading. First Language, 32(3), 343-364.

  23. Eason, S.H., Nelson, A.E., Dearing, E., Levine, S.C. (2021). Facilitating young children's numeracy talk in play: The role of parent prompts. Journal of Experimental Child Psychology, 207:105124.

  24. Duncan, G.J., Dowsett, C.J., Claessens, A., Magnuson, K., Huston, A.C., Klebanov, P., Pagani, L.S., Feinstein, L., Engel, M., Brooks-Gunn, J., Sexton, H., Duckworth, K., Japel, C. School readiness and later achievement. Developmental Psychology. 2007;43(6):1428 – 46.