The developing child
Map of the chapter
In this chapter, we start by looking at the way the brain develops from birth to adolescence and consider the main ways in which areas of the brain and brain activity are linked to particular abilities and behaviours. Recent research from the field of neuroscience enables us to understand these processes much more clearly than before and provides important insights into all aspects of child development. Of course, children are born into a particular social context, so in this chapter we also consider in a broad way the impact of family, community and wider society. There are complex interactions between biological, socio-economic, health, educational and socio-emotional factors in any child’s development. Here we consider some of the wide discrepancies in the experiences of children and young people within our own society and the impact that this has on their development. Bronfenbrenner’s influential ecological model of human development provides a useful framework which underpins the argument in the chapters that follow.
The brain
The brain of the foetus develops very early and by the time the baby is born, the main structure and all the neurons are present. Even at such an early age, the infant brain resembles the adult brain, although it is only about 25% of its weight, so the newborn baby is capable of organized sensation, perception, attention, memory and learning. At the same time, the infant brain is flexible enough to allow for adaptation to the context in which the child has been born.
The human brain consists of different areas, each of which is associated with certain faculties (Haines, 2004). As you see in Figure 1.1, the temporal lobes are involved with memory; frontal lobes and prefrontal cortex with planning and with the regulation of emotions. For detailed diagrams of the structure and systems of the adult brain, see Haines (2004). The brain is made up of billions of cells called neurons which transmit signals to one another in organized networks. Neurons are the information storage and transfer components of the central nervous system (Figure 1.2).
Neurons code and transfer information in the form of electrochemical currents that travel from the cell body along the axons to the axon terminals. Information is transmitted to the next cell at a junction called the synapse by chemicals called neurotransmitters. At the top of the neurons are branch-like dendrites which allow contact with other neurons and which in this way form networks. When stimulated, neurons propel a small charge or impulse which passes from one neuron to another across tiny gaps, called synapses. These connections allow complex networks of neural activity that underlie the function of the brain and the nervous system.
In the months after birth, the process of developing the connections, or synapses, of the adult brain makes rapid progress. The cells become more complex, growing more dendrites and axon terminals and making an increasing number of synaptic connections. At birth, the cells are ready to respond to sensory input, such as sights and sounds, and, as the baby experiences these stimuli, some synapses and cells are used more often than others and these connections are strengthened. By the age of two years, a single neuron may have as many as 10,000 different connections to other cells! It is because of these myriad connections that the infant develops so quickly both behaviourally and cognitively. At birth, many areas of the brain do not yet have a specialist function. The earliest regions to develop are the brain areas for sensory processing, including the visual cortex. Later, these processes occur in the language area of the brain. Later still, the frontal lobes develop a large amount of synaptic growth throughout childhood.
Innovatory work in the field of neuroscience enables researchers to map patterns of activity in the brain and we now know that new brain pathways and patterns are built to encode new memories and learning right across the lifespan from the earliest years. For example, Meltzoff, Ramirez, Saby, Larson, Taulu and Marshall (2017) carried out experiments, using neuroimaging, about the way in which infant brains represent the human body, both their own and that of others. In the first experiment, the researchers lightly tapped the hand and foot of seven-month-old babies and found significant activation in the hand and foot areas in the contralateral primary somatosensory cortex, as well as in other parietal and frontal areas. In the second experiment, the researchers investigated the infant brain responses to visually perceiving another person’s hand or foot being touched. There was similar activation in the early visual regions and in regions thought to be involved in multisensory body and self-other processing. Furthermore, in some, though not all, of the babies, the observed touch of hand and foot activated the infants’ own primary somatosensory cortex, though less consistently than when the babies’ own hands and feet were touched. This study has interesting implications for our understanding of early social cognition, including the baby’s capacity for imitation which, the authors argue, may build on infants’ neural representations that map equivalences between the bodies of self and other.
Parents are often amazed when they observe that their infants can imitate the parents’ actions, such as hand gestures or sticking out the tongue. Meltzoff et al. (2017) suggest that their study gives important insights into the infant’s emergent sense of the connections between the bodies of self and other. They speculate that infants develop a visual category for ‘hands’ in such a way that the hands of self and other share a common representation. Future studies in neuroscience will provide crucial information on how neural body maps change with age. Such experiments will help us to understand how infants can so quickly learn such interpersonal skills as bodily imitations and, later, attributions of intentions to other people. These capacities appear to build on infant neural representations that map equivalences between the bodies of self and other. We return to this theme in Chapter 2, where we explore the emergence of the concept of self during infancy and childhood.
The brain continues to develop throughout childhood leading to changes in both structure and function. During infancy and childhood, the number of synapses increases dramatically. However, at puberty, there is a change in the number of synapses within the prefrontal cortex, through a process of synaptic ‘pruning’. This results in more efficient transmission of information to the brain. In the prefrontal cortex, this process of synaptic pruning continues throughout adolescence. Major changes in the brain also take place during and after puberty, as you see in Table 1.1.
Table 1.1 Changes in the adolescent brain and their implications.
Source: adapted from Smith, Cowie and Blades (2015, p. 658)
Adolescence marks an important transition from childhood into adulthood. There are substantial changes with the onset of puberty, including increases in adrenal and gonadal hormones, which are linked to the development of sexual characteristics and can influence brain function. The fluctuation of hormones may provide an explanation for the functional differences in subcortical activity between children and adolescents, as opposed to activity in the prefrontal region which reflects linear change with age (Blakemore, 2018). The prefrontal regions guide actions. So immature prefrontal activity might hinder appropriate estimation of future outcomes, especially when making decisions within an emotional context. Steinberg (2004) argues that risky behaviour and emotional reactivity in adolescence are the products of this imbalance between increased sensation-seeking in conjunction with immature self-regulatory competence. This would explain certain aspects of adolescent behaviour. Adolescence is a time in which there is an increase in the likelihood of harm, such as injury, accident, drug and alcohol misuse. Adolescence is also a time when symptoms of psychiatric disorders emerge. It is possible that the imbalance during adolescence between emotion processing in subcortical regions and modulatory emotional regulation in prefrontal regions may play a role in the increased risk for mental health difficulties during adolescence. Aspects of mental health are discussed in more detail in Chapter 9. This is further discussed in the chapters that follow where we explore addictions, bullying and violence and risky sexual behaviour.
At the same time, there are wide individual variations influenced by such factors as the family, the school, the community and the wider society. In the next section, we look at environmental influences that interact with the child’s developing brain processes.
Health in childhood and adolescence
Children and young people are physically healthier in the twenty-first century than they were in the past and there are now many more professionals supporting families than ever before. In the twenty-first century, infant mortality rates in the UK are generally low, at less than 0.1% of the child population. This was not always the case. At the beginning of the nineteenth century, around 10% of children did not survive their first year of life. Among the poor, this rate was 20%. Causes of death included epidemics of measles, scarlet fever, whooping cough as well as poor nutrition, contaminated water and environmental factors such as low-standard housing. Despite the advances in education, health and social care for children, there are still major concerns. There remain unacceptable health variations among different social groups in the UK. Serious outcomes are that families living in poverty experience poorer health, have reduced life expectancy and, in some areas of the UK, have more difficulties in accessing health resources (Vydelingum & Colliety, 2011; YoungMinds, 2017).
With regard to children’s emotional health and well-being, there is strong evidence for an increase in psychosocial disorders during childhood and adolescence (YoungMinds, 2017). As we indicate in Chapter 9, emotional and behavioural difficulties among children and young people have increased over the past four decades (Department of Health, 2014; National Society for the Prevention of Cruelty to Children, 2015). YoungMinds (2017) commissioned a survey of young people, their parents/carers and professionals to report on their experiences of participation in mental health services and found, among other disturbing issues, that stigma continues to surround mental health difficulties. Suicide is the second leading cause of death during childhood and adolescence compared with other age groups (Cha, Franz, Guzmán, Glenn, Kleiman and Nock, 2017). Today’s young people seem to face severe stresses that were unknown a generation ago.
Certain groups of young people are especially vulnerable, including young carers, looked-after children (children in care), children of asylum seekers and children living in disadvantaged areas. Current government policies aspire to achieve better health outcomes for children through provision of health, social and education services for all, and progress in minimizing health and educational inequalities. The infrastructure that contributes to continuing reductions in child death and illness includes policies for immunization against common childhood illnesses, systems for safe drinking water, safe food, improved housing conditions, better quality of air, road safety campaigns and wider knowledge about healthy eating and healthy lifestyles. Government policies provide a framework in which to deliver an array of services to meet the psychological as well as the physical needs of children and young people, including the issues of obesity, mental health, social health and teenage pregnancy.
The (UNICEF) Report Card series proposes that:
(UNICEF, 2010, p. 1)
Its recurring theme is that ‘protecting children during their vital, vulnerable years of growth is both the mark of a civilized society and the means of building a better future’ (ibid.). With this precept in mind, From Birth to Sixteen aims to give knowledgeable support and information to all those who work with children and young people, and who wish to give them the best opportunities possible for healthy development. The book is based in the belief that change is possible, whether it is facilitated at the level of society, of community, within the family or by individuals themselves. Resilience is a current theme which we discuss later in the book.
Bronfenbrenner’s ecological model of development
One very influential theory of child development is Bronfenbrenner’s (1979) ecological model of human development – a model that underpins From Birth to Sixteen since it takes account of development in a range of different contexts and does not only focus on individual characteristics of the child or young person. Ecology here refers to the environmental settings which the child or young person is experiencing or is linked to, directly and indirectly. Bronfenbrenner proposed that individuals develop in four nested systems:
Microsystem: This inner level refers to the experiences of the individual in a particular setting. For the young child, this is usually the home environment; for the older child or young person, this may be the school environment, with teachers and peers.
Mesosystem: This next level refers to links and interactions among settings that the individual directly participates in. For example, the quality of the child’s home environment might affect his or her academic performance in school or the nature of peer relationships.
Exosystem: This level refers to links with settings that the individual does not participate in directly but which have an influence on that person’s life. For example, the parent’s work environment may affect their physical health or their emotional well-being and so influence the quality of the care that they provide for their child.
Macrosystem: This level refers to the general pattern of ideology and organization of social institutions in the wider society in which th...