(PART I) Early Child Development from the scientific point of view
Why is early child development so crucial?
Studies from neuroscience, genetics as well as developmental and behavioural researches have established that early childhood development, in particular the early brain development from conception to preschool age1, lays the foundation for the individual's future development. It affects not only an individual's learning and school achievement, but also his physical and mental health, economic productivity and societal responsibility throughout the life course2. Understanding the process of brain development and the key contributing ingredients provide caregivers and professionals insights for child's optimal development. Having said so, many people have misinterpreted the concept, and may act too eagerly to find means, such as using gadgets, flashcards or specific music in the hope of boosting up children's brain power. However, so far there is no definite scientific evidence to map out the neural processes or environmental conditions to achieve superior cognitive functions from ordinary brain development 3, 4.
After conception, our brain begins to develop and nearly most of the brain cells are created in the prenatal period. During the first trimester of pregnancy, cells become differentiated in their functions according to their specific locations in the brain (e.g. hearing, touch, vision and language etc). Genetics provides the blueprint for the brain development, while early experiences determine how the genes are expressed. For the brain to function, neurons connect and communicate with each other via dendrites (neurons' signal-receiving fingers) and axons (neurons' signal-emitting extension), and circuits of communication are formed. The circuits which are frequently used and stimulated from environmental inputs and early experiences would be strengthened while the less frequently used ones would be removed or "pruned". Scientific research has found that there are sensitive periods when the brain is more sensitive to experiences and strong connections are formed for different senses, emotions, motor skills, behavioural control, logic, language, and memory. Different capacities have different sensitive periods. The sensory circuits of vision, hearing and touch develop first and lay a foundation before the more complex capabilities of higher cognitive functions such as the executive function and self-regulation can be built. These sensitive periods show us that children are unable to master skills when the corresponding brain circuits are not yet ready. If caregivers expect their young children to acquire advanced skills surpassing normal development, they may instead induce unnecessary stress and even impair healthy development of their brain8.
How early experiences shape brain development
Reciprocal "serve and return" interaction
One of the most significant experiences in shaping the developing brain lies in the "serve and return" interaction between the caregiver and the child in their daily lives. Infants have a natural tendency to initiate interaction with others by crying, babbling, facial expressions and non-verbal gestures. The caregivers, being aware of the infants' needs and wants, respond by directing their attention to the child through means like looking, smiling, imitating his gestures or vocalizing with the child. The actions continue in cycles between the dyad and that is called "serve and return" interactions9, 10. Sensitive and responsive caregiving not only helps children grow and thrive, but also provides the stimulation for building up connections among different parts of the brain, thus facilitates the development of the child's sensory (such as hearing, seeing, touching and smelling) capabilities, language, emotions and other higher cognitive functions. During this process, the caregiver and the child form a secure and trusting relationship through which the child gradually acquires an understanding of others' intention and social skills, a personal sense of control and mastery as well as resilience in the face of stress and challenges.
Supportive & caring relationship beyond the family
Infants would have already formed strong attachment as early as two to three months of age11 with their caregivers (not necessarily their parents) given that these attachment figures spend time with the child and provide warm, responsive care. Anyone in close contact with the family and the child, including relatives, neighbours, pre-primary teachers and other child related professionals, can help build important growth-promoting relationships and have significant impact on the child's early development10. The child benefits not only from the secure relationship with these important persons, but also from the ways these significant caregivers provide stimulating activities for brain development. They can also provide support for the child in developing positive social relationship with others.
Supportive and caring relationship in times of adversity 9
Another type of experience that may strengthen or weaken the brain development is stress. When we are under stress, our stress response system, including the autonomous nervous system and the limbic-hypothalamus-pituitary-adrenal axis, will be activated and elicit series of body reactions such as increased blood pressure and heart rate as well as heightened level of stress hormones in order to cope with the adversity6.
Children may experience stress of mild level, such as when meeting new people and having brief separation from caregivers, and of moderate level including being seriously ill, facing parental divorce or loss of a loved one. These difficult experiences can be growth-promoting for the child as long as the stress occurs in time-limited period and in the presence of a supportive and caring adult guiding the child to cope with these difficulties.
On the other hand, intense and persistent stress response in the child can be aroused by adversities such as extreme poverty, persistent abuse or neglect, parental substance abuse, severe maternal mood problem or exposure to violence. The prolonged activation and elevation of stress hormones without the supportive relationships are called "toxic stress" response. This kind of stress can disrupts the architecture of the developing brain, impedes a child's learning, memory and self-regulation, and results in higher susceptibility to stress-related physical and mental illnesses later in life. Apart from providing support to these families in adversity, it is also important to provide nurturing environment for the child, helping him to build a sturdy brain foundation early in life.