Is human psychology predominantly a function of nature or nurture?

Introduction (define key terms, outline argument and allude to essay answer/conclusion)Contrasting views exist on the extent to which human psychology is influenced by forces nature or nurture. Proponents of the role of nature largely concern themselves with how genetics and innate abilities drive behaviour, while those who advocate nurture argue that it is the environment that predominantly shapes individuals' personality and behaviours. Both sides of the debate can draw upon particular methodologies, namely twin and adoption studies, and different key approaches within psychology to support their arguments. Ultimately however, as exemplified by gender development suggests, it is an interaction between both nature and nurture that provides a comprehensive explanation of human psychology and its determinants. Argument for Nature - Concerned with how genetics and innate abilities influence behaviour. In twin studies, similarities and differences are investigated in genetically identical (monozygotic) and non-identical (dizygotic) siblings. Concordance rates (a measure of similarity) are calculated for a whole host of psychological traits, such as intelligence and personality composition. That monozygotic twins are consistently more psychologically similar (higher concordance rates) than dizygotic twins does postulate the idea that nature has a large influence on human psychology. However, a lack of a perfect concordance rate between monozygotic twins that have been raised together has led researchers to study 'unshared environments' that help distinguish between the influence of nature and nurture. Although, this does not mean that twins living in the same environment cannot also have 'unshared' elements of their environment, and will often experience a variety of stimuli, such as accidents or illness. Plomin et al, a proponent of a biological approach to psychology, has shown that monozygotic twins will achieve more similar GCSE and A level results than dizygotic twins, regardless of the environment. If intelligence is genetic, it may be argued that it is not feasible for society to invest time and resources into intelligence enrichment programmes. Argument for Nurture - The environment shapes an individual's personality and behaviours, and has a greater impact on the phenotype (visible characteristics) than genetics. Twin studies are also used to buttress the nurture position. If monozygotic twins reared apart have a low concordance rate, it will show support for nurture. More significantly, a well-respected approach within psychology demonstrates the adoption of a nurture stance. According to John Locke, a key founder of behaviourism, we are born 'tabula rasa' - a blank slate - referring to our lack of innate aspects. Following this is the assumption of environmental determinism, that is all behaviours are simply responses to stimuli in the environment. Even complex behaviours are just a series of stimuli-response links. B.F. Skinner's studies with rats establishing the principles of operant conditioning (that behaviour can be made more or less frequent by reinforcement or punishment respectively) provides a strong evidence of the environmental impact on behaviour. Adopting a nurture stance has allowed the development of useful treatments, such as behavioural therapies. For instance biofeedback is often used to treat the physiological response to stress, by reinforcing (rewarding) an individual when they are successfully able to calm themselves. Interaction While both nature and nurture are useful in understanding particular facets of human psychology, neither on their own can provide a comprehensive account. The topic of gender development presents a case in point. While a biological approach might assert that the biological sex of an individual determines gender development - the presence of the Y sex chromosome stimulates the production of testosterones, which drives masculinisation of the brain - that gender development is not universal does suggest that it is not purely biological. Many individuals in today's society are increasingly identifying as members of the opposite gender, or as non-binary where they do not identify as either strictly male or female. This presents the view that there is also a social, and thus environmental, component to gender development. Social Learning Theory would support this, as they suggest a great deal of gender learning stems from the interaction of an individual their their social environment, and how behaviours are imitated and internalised off a model.