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Describe the process by which genes and environment operate together to influence development. Discuss the significance of these processes for our understanding of child development.
This essay will give a detailed account of the process by which genes and the environment operate together to influence development. Looking at Physical development and Language development and the perspectives of Natavism, Behaviourism. Constructivism and Social Constructivism it will explain the role of these perspectives in understanding child development. It is argued that the genetic blueprint can interact with the environment to encourage development. The process of genes and environment working together is often referred to as epigenetics and shows how environmental factors which can affect a parent can change the types of genes passed onto their children.
Looking at Physical Development it can be seen if the process of genes and environment operating together influence development. As the environment is constantly changing humankind needs to have changeable characteristics, some of which are physical, this is known as “Developmental Plasticity”. Piaget studied water snails and found that shape of the snails shell varied depending on its habitat. Pond snails had longer shells than lake snails who had shorter shells to suit the water turbulence. Suggesting that cells have the properties to change and become “self-organising”, cells can change the way they are developing in response to environmental stimuli. It is argued that genes can be switched “on” or “off” in response to this environmental stimuli and can alter the characteristics they produce.
“Piaget called this process “Epigenetic Development”, Epigenetic information is constantly being acquired throughout development, giving the environment an active role in influencing development. The environment is shaping information in our genes and changing our physical development. Humankind standing on two legs and walking was a response to environmental changes. This has had a significant effect on our genetic makeup from the shape of our pelvis to the size of our skull.
Epigenetic systems can only change things during the period of maturation and once a characteristic is adapted it can not change back. Richardson, 1994, argues in relation to child development this would mean that once a child has learnt a particular behaviour this can not be changed or removed. Richardson argues because of our changing environment humankind need genetic characteristics which are changeable and can adapt through out a lifetime. We are constantly learning new things, and adapt our behaviour to what we have learnt.
Learning is one of the processes which require our behaviour patterns to adapt through our lifetime. Life long developmental plasticity is a form of epigenetic development more suitable to child development as aspects such as language, behaviour adapt to suit our environment. Other theories exist which explain the importance of genes and the environment in child development.
Belief that all human development can be explained by genetic make up is called genetic determination. This view sees behaviour as having end points and of humankind having little control over their development. The Genetic theories are rigid or Canalised systems.
Plotkin and Odling-Smee, 1979, argue genetic determination needs environment to remain constant for many years in order for advantages of adaptation and natural selection to emerge. This is unlikely to happen in our ever changing environment, humankind can change its own environment. This can be seen by the creation of nuclear weapons, and the cutting down of rainforests.
By studying twins and heritability it is possible to see to what extent genes influence our development. Heritability is what geneticists use to measure genetic differences, similarities are rated between 0 and 1. The higher the score the higher the heritability, indicating less genetic difference. Twins are usually reared in the same environment, monozygotic (identical) twins share the same genetic make up and dizygotic twins (non-identical) share only half of their genes. So if development is determined by an innate blueprint then monozygotic twins should have higher heritability characteristics. E.g. Temperament, intelligence etc. than dizygotic twins. Buss and Plomin, 1984, studied twins at 4 years of age and found identical twins were similar in emotionality, Activity and Sociability heritability. Non-identical twins showed no similarities. Buss and Plomin argues this was evidence of genetic influence on development. Berscheid and Walster, 1978, found problems with the relevance of twin studies it was suggested that because monozygotic twins looked alike they were more likely to be treated alike by parents and other members of the family. This could mean that their environmental influences were more similar than dizygotic twins.
To counteract this problem Buss and Loehlin, 1989, looked at twins who had been raised apart and found that monozygotic twins still had a high heritability for IQ. This suggests IQ could be genetic. Problems were also found with the relevance of this study it was suggested that it was difficult to find twins that had been reared apart. If the twins parted it was suggested by Komin, 1974, that most twins were then raised by different members of the same family in similar environments. Buss and Loehlin ignored the fact that the twins had shared the same womb environment before birth
Gesell a Natavist argues that development is the result of genetic influence. In “Gesell’s principles of Development” he argued, the developmental process followed by children, in particular motor development sequence, is provided by an innate program found in the genes. Gesell called this maturation and argued that the genetic blueprint could not be altered and there was little point in encouraging a child to try to learn things before this innate program was ready to learn. This was known as the “Genetic Program” for development . With this view there would be little point in pre-school education as children would not benefit form it. They would not be able to learn skills quicker than their genetic programming allowed.
Chomosky, 1980, argues genetic programs are the only way to understand physical and cognitive development. Natavism argues humans are born with innate programming and with several motor reflexes such as the rooting reflex. They argue this is evidence of genetic programming in the womb since at birth they have not been subject to any external environmental influences. Critics of Natavism would argue that it’s theories are based on observations and not on experiments and argue some of the skills shown by newborns which are thought of as innate do not take into account experiences of the environment in the womb. It does not consider the mother, or the how her lifestyle has affected the development of the infant. Decasper and Spence, 1986, asked pregnant women to read the same prose to their babies, and again after birth. It was shown babies preferred the prose that had been read to them in the womb over other pieces. This shows that environmental influences can not be ignored.
Bruner, 1983, argues that both innate skills and the environment work together to encourage language acquisition. Bruner argues that language needs an innate programme which helps a child learn language such as a Language Acquisition Device (LAD) as suggested by Chomosky, but Bruner agues this must be supported by a Language Acquisition Support System (LASS). The adults around the child provide support in a variety of ways. By using joint-action formats, the mother creates sequences and repeats them so the baby can learn. Bruner termed this sequence of interactions as scaffolding, the adult controls the situation to allow the child to progress. One example highlighted by Snow and Ferguson, 1977, in the way in which adults, particularly mothers talk to their babies. They use repetition and a different pitch of voiceis called motherese or baby talk. The interaction a child gets with the mother during baby talk helps provide the baby with an understanding of the social environment and the baby learns that language is part of a social interaction. Fernald, 1985, studied four month olds responses to normal voice tone and motherese. He found that the child favoured the motherese. Bruner argues it is through interactions like this that a child gains an understanding of the world and together with the child’s innate language ability a child can learn to follow a conversation. This shows the genes and the environment operating together to influence child development.
Chomosky argues environment can not explain the complexity of the mental structures, in particular language. In Chomosky’s study of language development he argues humans are born with a language acquisition device (LAD) which allows us to learn universal grammar language skills. An experiment by Trehub, 1988, confirmed that babies can have the ability for phonemic discrimination. Trehub’s study aimed to see if 1-4 moth old babies with English speaking parents could distinguish two sounds used in the Czech language. Trehub could not hear the two phonemes when listening to the tape supplied by a linguistics laboratory. The parents of the babies coud not tell, but the babies could tell the phonemes apart easily.
Skinner a behaviourist disagrees with Chomosky, Behaviourists argue child development is based on conditioning and imitation. Skinner argues children acquire language not innately but through reinforcement. Skinner argues adults try to interpret a child’s babbles into words and praise babbles that sound like words. Adults then reinforce the words by repeating them back to the child. The child then imitates the words of the adult and gains more praise for sounding like an adult.
“Behaviourists argue language is the result of the environment a child is in, as children do not invent new languages but acquire the language from the environment around them. Chomosky accepts environment does have a role to play in language development, as environment decides which language is learnt, but argues the capacity to learn language is innate.
Another way of looking at language development is the child constructs its own language acquisition. The Transaction Model by Sameroff, 1991, can be applied, this follows the pattern of gene and environment creating development but the child then reacts to the feedback of development and influences its own development. Sameroff argues that as a result of a difficult birth a mother could become anxious, creating a baby that is has irregular patterns of sleeping and feeding and the mother sees the baby as “difficult”. The mother will spend less time with the baby and as a result the child may not attain average language development. The child is seen as active in development and creates interactions which lead to development processes. Piaget also sees the child as active in language development. Piaget reflects the constructivism theory of child development, which sees genes and environment working together to influence development. Piaget argues children do construct their own language acquisition. Piaget accepts maturation and learning are part of language development but argues a child can construct its own knowledge through its environment. Piaget says that children are born with basic actions called sensorimotor schemes and build on these foundations through interaction with environment. Piaget argues in the first two years a child has no need for language. Piaget argues that language develops through shared experiences and knowledge of the world. Piaget’s theory had an impact on the world of education and how teachers viewed learning. If as Piaget argues children are active learners, methods of teaching which involve lecturing students and students taking notes would not be a productive method of teaching. Teaching methods which actively involve the child and encourage exploration and self-knowledge would be more productive. A move away from examination based education and the introduction of more course work based elements is a reflection of this theory in the world of education.
In contrast Vygotsky, a social constructivist disagreed with Piaget as his theory ignored the social environment. Vygotsky argued society was essential to child development as it allowed child interaction with others. He argued that language is acquired by the child “internalizing social interactions”. A child learns from another person and after interactions are repeated several times the child internalizes it. Vygotsky argued this can only be achieved with another person and carried out in the child’s “zone of proximal development”. Both Vygotsky and Piaget felt a child was active in the their own development. Vygotsky argues environment and its interactions shape the child, in contrast Piaget’s theory is more biologically linked.
In conclusion it can be seen from looking at physical development and language development that genes and the environment operate together to influence development. In relation to child development the gene-environment perspective is not the only one to be considered. Gene only perspectives, Environment only perspectives and the Transactional model which sees the child as actively shaping its own development all play important roles and help us to understand the process of child development.