The study of biological processes, particularly the nervous system (including the brain) and genetics has provided much relevant information for the study of psychology. This essay will look at how biology can help us to better understand some aspects of psychology. The reductionist and biological psychology approaches will be described, followed by some examples of how biology is helpful in understanding psychological explanations. These examples will lead us to the conclusion that biological knowledge can lead to a deeper and more detailed understanding of psychological explanations.
Looking at the biological basis for psychological phenomena can suggest explanations at a very detailed level. Reductionism describes a scientific perspective which asserts that psychological phenomena can only be fully explained by looking at exactly what is happening in terms of biological processes (Crick, 1994). A reductionist point of view applied to differences in the personalities of siblings would suggest that these differences can only be entirely explained by looking at differences in the sibling’s genes.
The reductionist approach is helpful in certain cases, but has little to offer in others – most psychologists with an interest in biology would agree that while biological explanations are helpful, not everything can be explained in these terms. An integrated approach is needed – biological and psychological processes interact in complex ways, and looking at biological processes along with environmental effects gives a better understanding in many areas of psychology. This integrated perspective is termed the biological psychology approach (Toates, 2002)
An understanding of biological processes can begin to explain how the functioning of the brain and nervous system, along with the environment, lead to specific behaviours. The biological approach can help explain psychological conditions such as depression, issues of cognitive interest – how the brain works during different types of behaviour, and can even shed light on differences in our personalities.
Depression provides an excellent example of how a biological process can illuminate a psychological explanation – leading to increased knowledge of the causes of depression. These causes are usually of both biological and ‘environmental’ origin. A genetic susceptibility to depression is believed to take the form of imbalances in neurotransmitters and other chemicals involved in the function of the brain. The neurotransmitter imbalances lead to the symptoms of depression.
These discoveries have enabled effective anti-depressant drugs to be designed. However, a biological imbalance is not the sole cause of depression and environmental factors must be considered. The genes may create a susceptibility to depression as described, but the condition may not manifest itself without the presence of traumatic life events. This facet of depression is often dealt with using psychotherapy and counselling. Thus, the knowledge that depression is usually caused by both biological and ‘environmental’ factors enables appropriate treatment to cover both areas, giving a better chance of recovery. Biological knowledge has thus given a much greater understanding of this area of psychology.
The study of the brain has become much more advanced with new technology that allows the brain to be imaged while the participant undergoes certain tasks. Positron emission tomography (PET) allows completely non-invasive study of the brain. Participants in such studies undergo brain scans while performing tasks such as recalling memories – and the region of brain involved can be seen to be active on the scan.
This allows comparisons to be made between different participants and large amounts of experimental data to be gathered so that links can be made between brain activity and the task in question. PET has also been used to look for dysfunction in the brain – for example, scans of the brains of violent criminals compared to control participants have revealed that the criminals often have under active frontal lobes – an area of the brain thought to control restraint (Toates, 2002). Brain imaging has huge potential for allowing psychologists to link different behaviours with changes or differences in brain structure and activity.
Psychologists who study personality are interested in whether there is evidence of a biological basis for differences in our personalities. This area of personality research was initiated by Eysenck, whose theory states that there is a link between key systems within the brain and fundamental areas of behaviour such as arousal levels, sensitivity to rewards/punishment and learning. Eysenck believed that differences in the activity of such areas of the brain – for example the limbic system (which controls our emotional responses) – leads to the differences we see in our personalities, in this case regarding the ‘neuroticism/emotional stability’ personality dimension – one of three dimensions of personality he describes (Eysenck, 1967). However, Eysenck’s evidence for these connections is weak. Despite this. his theory has generated a lot of further research regarding the biological basis of personality.
The biological basis of personality is commonly discussed in the ‘nature or nurture’ debate – whether our genes or our environment have a greater effect on making us ‘who we are’. Behaviour genetics studies investigate heritability – that is, what is the relative contribution of genetics to individual differences – in this case, differences in personality traits. The main method used to study heritability is twin studies, involving both identical (monozygotic) and non identical (dizygotic) twins.
Since monozygotic twins are genetically identical, if the genes play a large role in controlling personality traits, the monozygotic twins should be more similar than the dizygotic twins (Thomas, 2002). The results of such studies are used to calculate an estimate of heritability – overall, around 20 – 30% of individual differences in personality traits are thought to be due to genetics, with the rest being due to the environment (Lochlin, 1992). These studies clearly reveal the importance of the environment in which we grow up, but also tells us that some parts of our personality can definitely be inherited – nature and nurture are not separable.
The examples given above show that understanding biological processes gives a greater depth to psychological knowledge, and can lead to new areas of research. Understanding the physical details of what is happening during psychological events enables us to have a clearer picture of how some behaviours originate. The study of genetics allows us to investigate the inheritance of different psychological parameters, and to see how our genetic makeup can affect us psychologically. The further study of the brain and genes will surely lead to new information that in turn, can be applied to psychological theories and extend our knowledge of ourselves.
Crick (1994, cited in Toates, 2002)
Eysenck (1967, cited in Thomas, 2002)
Lochlin (1992, cited in Thomas, 2002)
Toates, F. (2002) ‘Biological Processes and psychological explanation’, in Miell, D., Phoenix, A. and Thomas, K. (eds) Mapping Psychology, Milton Keynes, The Open University, pp. 228-229, 268-270, 276.
Thomas, K. (2002) ‘The individual differences approach to personality’, in Miell, D., Phoenix, A. and Thomas, K. (eds) Mapping Psychology, Milton Keynes, The Open University, pp. 311-314, 318-323.
Commentary 4 in Miell, D., Phoenix, A. and Thomas, K. (eds) Mapping Psychology, Milton Keynes, The Open University, pp 283-287.
Lynne Watson – R3796354 – DSE212 TMA 02