Developmental psychology refers to the human development of cognitive abilities and social relationships across a lifetime (Colman, 2006). Understanding development has its importance as it provides insight into human behaviour. Over the years, a vast number of developmental theories that have aimed to offer insight into this matter have been put forward. The debate as to whether development is driven by nature (evolutionary processes) or nurture (environmental factors) or a combination of both fundamentally divides theories in the field and beyond (Maltby, Day & Macaskill, 2007). The aim of this essay is to identify and explore the distinctions between nature and nurture theories. Some examples of developmental theories, such as the Maturation Theory, Learning Theory, Nativist theory, and Cognitive theory will therefore be discussed to illustrate these differences. Although the main topic of this essay is that of showing the distinction between nature and nurture theories, some scientists suggest that in order to understand human development it is important to look at how nature and nurture interconnect not so much to stress the differences between the two (Lerner, 2002). Therefore the interconnections of nature and nurture will be also briefly discussed.
Naturists believe that the knowledge humans have about the world is innate. Therefore human development is largely determined by heredity. Conversely, nurturists believe that is the environment which shapes and influences human behaviour. Some early nurturists, such as John Locke have put forward the extreme idea that humans come into this world as 'blank slates' which will later be filled with knowledge acquired by learning and experience (Gross).
Nature and nurture represent two radical points of view within the theories of development as if only one or the other would have all the answers as to account about how and why human development happen as it does. These radical views were easy identifiable in the early theories of development such as Gesell's Maturation Theory (MT) and Watson's Learning Theory (LT) (Gross)
Gesell (1925) believes that maturation is driven by inner, biological factors and that the child's development happens in stages. Conversely, Watson (1925) believed that it is the environment that shapes the human development (Daly, 2004). Watson suggested that the child comes into the world as a 'blank slate' ready to be mould by the experiences he/she will have in the outside world. Ultimately, the environment will determine the direction of human development. For Watson (1925) the developmental process of behaviour is continuous as oppose to gradual as Gessell (1925) proposed (Shaffer). In addition, Watson argued that the nurturist approach is more viable as his findings were obtained by overt observation of human behaviour as opposed to inner, biological forces as described by Gessell which cannot be observed. (Watson).
In order to show just how easy children can learn fear and other emotions, Watson has run an experiment with a 9 month old baby called Albert. When Albert was firstly presented with a white rat he played with the rat and showed no fear. After two months, Watson repeated the experiment only that this time a noise was introduced every time baby Albert reached for the rat. Baby Albert learned very quickly to associate fear with the presence of rat. Watson's conclusions were that conditioned emotional responses are learned and they persist. As a result this is what modifies and influences the changes in human development time and time again (Watson). On the other hand Gesell looked at children's psychomotor development (e.g., grasping) and locomotion (e.g. crawling) and draw the conclusion that these abilities are dictated by the genetic material with which the child is born. These abilities develop naturally determined by an innate timetable, providing that the child is healthy and normal. (Gross) Therefore human development is dictated solely by heredity (Daly). These examples are relevant to the essay question as they underline very well the extreme differences between nature and nurture theories.
Another way in which the distinction between nature and nurture theories can be observed is to think about language acquisition. Chomsky put forward the Naturist theory (NT) and suggested that humans are born with an inbuilt language devise. Skinner, on the other hand considers that human learn language as they do with any other behavior. Skinner has put forward to kinds of conditioning: classical and operant. In the classical conditioning he suggests that the child learns by association. For instance, if the word chocolate is followed by chocolate tasting, the child will soon learn that every time he hears the word chocolate will salivate because he/she associates the word with the sweet taste of chocolate. In the operant conditioning children learn by reinforcement (punishment or reward). Therefore learning language is all about nurture (environment, experience). Chomsky thinks that language is used creatively and that the LAD is activated by the environment at a certain age otherwise it will not happen. For example, Jeanine a 13 year old who was kept in isolation by her father was not exposed to language. She was never able to use language properly again. This backs up Chomsky hypothesis that language is innate and if it is not learned by a certain age it will never be acquired. These theories are yet another example of how different the views of naturist are in comparison with nurturists.
However, all these theories that have been discussed so far in order to underline the distinction between nature and nurture fail in one way or another to construct the whole picture of how human development happens. Maybe a better insight into human development will be therefore obtained by looking at the interconnection of nature and nurture as Piaget explained when he put forward his Cognitive Theory. Piaget saw develeopemnt in a different manner. He believed that humans are born with biological ability of adapting to environament. In other words, humans are coming into this world genetically predisposed to develop and acquire knowledge and inteligence. Piaget idea was developed around two major concepts: assimilation and accomodation. Assimilation refers to the fact the humans have the cappacity to assimiltate new information and integrate it into already established structures. HE named these already exisiting structures schemata or the mental structure. Accomodation refers to the change which takes place in the mental structure that already exisit in order to make space for new incoming knowledge. Intelligence is highly dependent upon the interconnection bewteeen assimilation and association. Piaget also believed that development happens in stages and that younger children think different then older children and adults. He identified 4 stages: sensori motor, pre-operational, concrete operational , formal operational. Piaget through his cognitive theory identified the importance of understanding that human development cannot be sexplaiend entierly just by taking into account the only the nature factor or only the nurture factorolely. The genetic material with which humans come into the world needs and environment in order to develop and grow and also the environment cannot influence a entirely a 'blank slate'.
To summaries, as shown an enormous amount of work has gone into studies set out to investigate the human development. Moreover, these theories have looked at how humans develop their personality, intelligence, how they interact with family and peers and how that affects their development and what forces drives this development. Although plenty of evidence has been presented in order to support either side in this nature versus nurture debate it seems almost illogical to try and think that human development can be either influenced only by nature or nurture. The most logical evidence so far has been provided by those scientists who have suggested that there is the interconnection of nature and nurture which drives development, shapes human personality and behaviour and makes humans who they are. Piaget maybe one of the most active researcher in this field has shown that human behaviour cannot be understood by only taking into account just the nature aspect or just the nurture aspect. Nature and nurture interconnect, human development cannot happen without one or the other. The genetic material with which humans come into the world needs and environment in order develop and grow and also the environment cannot shape entirely a 'blank slate'. A better insight into human development can be obtained if scientists focus more on the interconnection between nature and nurture rather than looking at the differences between the two.