The nature-nurture argument is ongoing and central to the study of behaviour and human psychology. It helps to stimulate research and discussion and keep the subject alive. Each side represents a perspective on behaviour its origins and how it might be modified when desired. On the nature side are geneticists who attribute behaviour to genes, and on the nurture side are the psychologists who support the pre-eminence of environmental influences.
Attributes such as hair, skin and eye colour are inextricably tied in with genetics and this can be proven experimentally. Some behavioural attributes can be tied to species specific genetic or physiological makeup (eg carnivores are aggressive, frogs croak, birds fly), but there is a lot of scope for individual behavioural characteristics (outside of the species ones) to be acquired through environmental influences such as role modeling, social hierarchies, habitat, and other events.
Prior to the scientific age, personality attributes and illnesses were often attributed to the works of Gods and spirits. After major discoveries in biology, genetics became the new favourite underlying influence and, when no other obvious cause was evident, genetics was selected as probable cause. However, this was before the decyphering of the human genome. Now it is clear that there are insufficient genes to account for all the characteristics previously assumed to be genetic in origin and we have to look elsewhere.
The following are two environments that have been overlooked in the excitement to understand the influence of DNA molecules and record the human genome, and have not been given the attention they deserve:
The womb of the growing foetus is an environment that affects the development of the infant. That environment is heavily influenced by the mother's behaviour, what she eats and what she does. There are many emerging theories about how the womb environment changes from one pregnancy to the next and how the growing foetus picks up sounds and movements from outside.
Development of characteristics in response to environmental influences begins well before birth.
The cell contains many components, all held within a fluid environment by a semi permeable membrane. The new foetus inherits a combination of the environments of the egg cell and sperm cell at the moment of conception. The nature of these micro-environments is dependent on many aspects of the behaviour of the parents and is much more open to behavioural influence than the genes are.
Twin studies, which compare similarities between identical and non-identical twins, where the womb environment is ruled out as a confounding factor, cannot rule out the cell environment as one. In fact any study at this time of genetic influence cannot rule out the cell environment. We simply do not know what, if any influence it might have on inherited characteristics. SImply put: genes may not be the only means of transfer of biological and behavioural characteristics, the environment of the cell itself, which is also transferred at conception, may also carry important qualities.
In the nature-nurture argument, if we take the side of nature, then we take a position in which we assume that there is not the ability to change, that characteristics are fixed by some force outside our control, or can only be changed through some biological intervention involving microscopes and test tubes. If we take the nurture side then we take a position in which we assume there is the ability to change through change in environment or behaviour. In many respects the nature side is sensible, because for instance, it would be ridiculous to think that we could change species within a lifetime (although over a thousand consecutive lifetimes this might be possible). There are, then, many aspects to our nature which are inviolable (within our lifetime at least). There are, however, many aspects of our nature which we can change. There is probably no clear line between what we can change and what we cannot, but each type of change probably involves a different level of difficulty. Species can only change very slowly over long periods of time. Human personalities and abilities, however, can change more quickly. Both kinds of change are related and both require the motivation for change in the first place, which usually comes from the environment.
The Power of Nurture
Nature cannot provide the motivation for change, only the environment (nurture) can.
Ultimately the environment plays a part in the development of any characteristic. Given enough time and motivation any characteristic can change. However for the purpose of this document we will deal only with those very human characteristics that can be changed during the lifetime and which are embodied in the concept of functional development.
Functional development requires a nurture perspective, since it involves focus on the effects that environmental influences can have on behaviour. The thinking here is that genes determine species while functional development determines character.
When discussing functional development in this document we will assume we are dealing with characteristics which are not species specific or driven by factors such as genes that would take more than a lifetime to change. There is also the assumption that functional development becomes so ingrained by the time of adolescence that any ability to change after that time requires very powerful motivating forces and considerable time and effort. In other words: change 'aint easy.