This bestselling textbook provides social science students with an accessible introduction to neuroscience and the implications for our understandings of child development, considering the links between brain development and social and cultural issues.
Now covering the 0-18+ age range, the new edition critically analyses the relationship between children and young people’s thoughts, behaviours and feelings and the ways in which their developing brains are structured. It includes a new section on emotional development in adolescence, considering the impact of drugs and alcohol on the brain and the role of brain changes in driving risky behaviours.
Assuming no prior knowledge of the subject, the text connects the latest scientific knowledge to the practice of understanding and working with children. Incorporating the latest research and debate throughout, the book offers students and practitioners working with children:
case studies showing how brain science is changing practice;
a companion website including self-test questions;
end-of-chapter summaries, further reading and questions to test knowledge;
In this chapter we begin by exploring the central nervous system and introduce you to some of its important elements. We begin with the outer crinkly layer, the cerebral cortex, and describe the main divisions. We then look at the subcortical brain and introduce the different parts of this such as the cerebellum, the amygdala and the hippocampus. We spend some time explaining the terms used to describe navigation through the brain. Terms such as ‘up’, ‘down’, ‘top’ and ‘bottom’ are not sufficient to describe human brains: something might be at the top when we stand up but would be somewhere else when we lie down!
We explore the different types of cells that are found in the brain such as neurons, dendrites, oligodendrocytes and astrocytes. Finally, we take a critical look at the process of picturing the brain. Many people assume that these wonderful, coloured images we see are photographs of the brain. We show this is far from the truth and consider the limitations of our abilities to really see what is happening inside our heads and, of course, the heads of children.
The development of the human brain begins very soon after conception and continues beyond adolescence into the late 20s or early 30s. While much of the development takes place within the womb, humans are unique in that a great deal of the brain develops postnatally, that is, after birth. Changes in brain structure occur throughout the lifespan, even into old age.
Life begins with the joining of a sperm and an egg. This leads to the creation of a two-celled organism that is called a zygote (meaning joined or yoked).
These two cells begin to divide and then divide again until after about a week there are approximately 100 cells. This cluster of cells is called a blastocyst (meaning bud or sprout). The cluster having got to this stage, a complicated set of changes begins to occur that leads to the formation of the different layers that eventually form parts of the body. The inner layer, which is called an embryoblast, will form the embryo, while the outer part, which is called the trophoblast, will form the external supporting tissues such as the placenta, umbilical cord and amniotic sac.
Developing an awareness that the physical world exists beyond our own senses is a major development in infant cognition. Early theories of child cognition based a large part of their research on trying to understand how infants begin to learn about their physical world. It is a large task to begin to comprehend a three-dimensional world through sensory processing. Infants have sensory systems and motor skills to enable them to explore the physical world. Through singular and combined sensory input and motor exploration, they gradually learn about various physical properties around them such as the solidity of objects and that the three-dimensional physical world exists outside of themselves. A key topic in infant cognition is how children learn object permanence, namely that a psychical world exists in space and time independently from themselves.
To understand this, infants need to develop the ability to perceive objects and realise that an object is the same even when it is moving in space. Shape constancy is this tendency to perceive the shape of an object as constant despite differences in the viewing angle (and consequent differences in the shape of the pattern projected on the retina of the eye).
Modern research has recast our thinking on how children perceive objects, and new techniques have allowed us to better understand the basic mechanisms of object perception in infancy. Object perception is thought to be mediated by two separable cortical regions and visual pathways, the ventral and dorsal pathways.
This chapter covers a broad range of issues around the relationship between what we put into the bodies of developing infants, children and young people and consequent brain development. We begin with food and diet and provide evidence to show that poor diet and poverty can have a devastating effect on brain development. We consider the problem in many parts of the world of simply getting enough to eat and look at the role of protein and fatty acids in building a healthy brain. In the second half of the chapter, we move away from food and look at the consequences of other substances such as drugs, cigarettes and alcohol on brain development. We evaluate the effect of these on the developing foetus and on the brains of teenagers.
The urgent bawl of a newborn baby would suggest that there is a capacity for emotional expression from the get-go, even if the range is somewhat limited. Yet we cannot be sure that what we are seeing is the expression of a discrete emotion such as anger or sadness or rather something more basic and undifferentiated that cannot be understood as a specific emotional expression.
Are emotions developed or constructed? There are two distinct paradigms. There are those who see emotions are ‘natural’, arising from distinct neural pathways in the brain that are present at birth. This paradigm seeks to understand which emotions are present at birth and which develop during the early years of life. This is sometimes referred to as a locationist model as it seeks to locate emotions in discrete areas of the brain.
The second paradigm is proposed by the constructionist school. In this approach emotions are seen as being constructed of basic psychological processes. Emotional experiences are created in the mind, are not located in specific brain areas and are dependent on language for their construction.
We begin this chapter with a critical account of attachment theory and then consider how neuroscientific knowledge is furthering, or in some cases limiting, our understanding of these theories. We briefly explore the relationship between attachment and childhood adversity and consider the question: does one lead to the other? We then explore what we know about the effect of poor and potentially damaging childhood experiences and consider the brain research in this area. We look at the areas of the brain that have been most fully researched: predominantly the amygdala, the hippocampus, the prefrontal cortex and the hypothalamic-pituitary-adrenal axis. Lastly, we look at the work that has taken place to investigate the plight of Romanian orphans, victims of the ill-fated Ceauşescu regime of the period 1965–1989.
The concept of attachment was developed in the 1950s by several researchers, although it is usually credited primarily to the psychologist and psychoanalyst John Bowlby. The work of Bowlby, alongside his colleague Mary Ainsworth in the United Kingdom and Harry Harlow in the United States, fundamentally and irrevocably changed our understanding of the relationship between infants and parents. Bowlby presented evidence from studies of both humans and animals to demonstrate his theory, including Konrad Lorenz’s work on imprinting and Harry Harlow’s work with Rhesus monkeys. This latter work showed, for example, that young monkeys separated from their mother will prefer to cling to a cloth-covered wire doll rather than a bare wire doll, even if it is the bare wire doll that provides them with milk.
Language is a uniquely human phenomenon. While other species can communicate with each other in all sorts of sophisticated ways, from the songs of humpback whales to the dances of bees, there is no other species that has developed language in the same way that humans have. Whenever we look at the communication of other species, we find that it has severe limitations that our own complex language system can overcome. For example, human language can express new ideas in ways which have never been said before. Our languages have words that, with a reasonable degree of consistency, retain their meanings across time. We can use language to reflect and record our experiences. Most importantly, our language has structure and grammar, which gives it an order and logic that is not contained in any animal communication. Our language is also something that is learned, something that depends on the language that is spoken by others around us. It is the way in which it is learned that has been the subject of a great deal of study and considerable disagreement.
In this chapter we argue that while language development is an innate human capacity, infants and children respond positively to an environment where they hear language spoken and have the opportunity to develop and practise these skills for themselves. As elsewhere in this book, we also argue that factors such as poverty, deprivation, neglect and abuse have a negative impact on all forms of development, focusing here on how these impact on language development.
While the learning of language might be a natural process, reading is a highly unnatural activity; in fact, according to David Wren it is one of the most unnatural things we do. Reading is a cultural activity, developed only about 5,500 years ago. For most children, many aspects of reading need to be explicitly taught and only improve with practice. Often, learning to read requires a lot of hard work. Exactly how the skills are taught remains controversial, even though in the United Kingdom one method, synthetic phonics, is now mandatory.
Keith Stanovich has noted that when it comes to reading ability, the more children do of it, the better they get at it. He termed this the ‘Matthew effect’ because in literacy terms the rich always get richer and the poor always get poorer. Good readers tend to read more and so their reading improves. Poor readers tend to read less and so their reading falls further and further behind that of their more literate contemporaries.
Reading is a highly complex process involving several different areas of the brain, including visual and auditory processing areas as well as aspects of short-term memory. To read and understand a passage such as the one that you are now reading, a complex array of brain-based skills need to be utilised. These include regulation of eye movements, decoding a visual sign into a sound, making meaning from this sign and then holding this meaning in the memory.
A key theme in this book has been that brain development is dependent on experience. Of course, nowhere is this more obvious than when we consider learning and memory. In Chapter 2 we distinguished between experience-expectant development and experience-dependent development. In brief, experience-expectant development involves the overproduction of synapses; some of these are used and retained while others are pruned away. This process of synaptogenesis and pruning happens first in the visual and auditory parts of the brain, then in the parts devoted to language and lastly in the prefrontal cortex. Experience-dependent development occurs over the course of the lifespan and equates to the process of learning and then storing in memory what has been learned. It involves the generation of new neural connections and the modification of existing connections.
We can see that learning and memory are highly interdependent. Explicit memory systems allow for the recall and reprocessing of experience. Learning is usually seen as a process that has the potential to change either knowledge or behaviour or, sometimes, both. There are many different ways of learning, and we explore some of them in this chapter. Likewise, human memory seems to be not one single system but a series of different systems, all of which operate and develop distinctively. In this chapter we begin by exploring the development of different types of memory systems and then go on to look at how these relate to different types of learning.