Relationship between biology and psychology Essay

What does an understanding of biological processes offer to psychological explanations? Support your argument with examples and research.

To understand psychological disorders, such as depression or those caused by brain injury, we need to consider their cause. The reductionist approach to this, exemplified by biologist Francis Crick, argues that all psychological events can be reduced to scientific explanation alone, focusing on a purely biological basis of psychological events and ignoring influences such as, social or environmental (Crick, 1994).

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In contrast, it is argued that psychological phenomena are the product of an interdependent and complementary mix of nature and nurture, integrating aspects of biology, genetics and psychology. This multidisciplinary approach, it is claimed, gains fuller understanding, providing mutually informative insight into emergent properties, such as behaviour, emotion and cognition (Bolton and Hill, 1996; Stevens, 1996; Toates, 2001).

So, what is the role of biology when considering psychological issues? Furthermore, does the reductionist dichotomy of biology and psychology lead to adequate understanding of human behaviour? If, on the other hand, a relationship between biology and psychology is considered reciprocal, what does this contribute to psychological analysis and treatment?

This essay will look at biological processes associated with behaviour, based on evidence produced from selected studies, to illuminate this debate and address these questions.

Biological processes of interest to psychologists concern the brain and nervous system. The brain has a right and left hemisphere which are divided into lobes, each with particular associated functions. Neurons are specialized electrically charged cells, specific to the brain and nervous system, responsible for transfer of information. Action potentials travel down the neuronal process to the presynaptic neuron where they stimulate the release of chemical �key-like’ neurotransmitters into the synaptic junction between cells. These are either excitatory or inhibitory and engage with matching �lock-like’ neighbouring cell receptors in the post-synaptic neuron. Neurotransmitters are then deactivated by enzymes present at the synapse.

Abnormality in activity at the synapse, which can be caused by disease, injury or drug use, is thought to be the basis of psychological disorder – depression and mood disturbances, for example (Toates, p. 249). This points to a link between biology and psychology. The reductionist perspective regards this as cause and effect, supported by material evidence from the areas of biochemistry, genetics and neurophysiology. For example, brain imaging techniques offer a look at what – or which brain region – is functioning.

Scientists now have the knowledge to retrospectively established a link between the damage received to the pre-frontal lobe in Phineus Gage, a railroad worker, and his subsequent personality and behavioural changes, concluding that trauma to this specific brain area was responsible for his lack of inhibition of inappropriate behaviour (Macmillan, 1986; Damasio, 1996). Using material data, therefore, helps explain abnormal psychological findings at a functional level. However, the brain is a remarkable organ and it is unclear if collateral neural networks take over the function of injured areas. Additionally, it is not possible to use controls which questions legitimacy of evidence.

Technological advancements have enriched investigation further, to include evidence on how the brain works using PET12 scans to collect �live’data. However, this introduces a harder to define qualititative element to analysis.

Looking at the phenomenon of depression further highlights the biology and psychology relationship. Stability of mood has been linked to a specific group of serotonergic neurotransmitters: depleted serotonin is thought to lead to depression. The process of reuptake of serotonin into the neuron can be decreased by blocking the enzyme responsible for serononergic neurotransmitter deactivation. Thus, serotonin remains longer in the serotonergic synapse and thereby lead to improved well-being (Toates, p.257). This is how anti-depressants such as Prozac work. This supports the approach that understanding biological processes such as these is of benefit to psychological understanding. But is this the whole picture? If the importance of social context and environment is acknowledged in parallel with biology, then other factors such as, thoughts, meanings and environment, become an integral part of the disorder.

The placebo effect study by Wall (Wall, 1993) on patients receiving pain relief demonstrated this. Despite substitution of the analgesic Morphine with an inert substance, efficacy was still experienced. Wall argues that this was because the individual believed the drug to be potent. Taking this a step further, if we consider a combined medication and psychotherapy approach for depression, it becomes impossible to determine if outcome is due to patient belief, counsellor’s attitude or medication effect. This highlights that reductionism privileges low level analysis of function, but neglects higher level analysis based on psychological factors such as meaning and experience. Furthermore, low level analysis is inadequate to explain similarities and differences with in groups. However, higher qualitative analysis can be difficult and unclear.

A reductionist perspective argues that genotype dictates not only hair colour and height, but physiological function and disfunction. Specific events are, therefore, predetermined in our genes. However, stress events or social context can trigger or cushion a predisposition, and the relationship between the two is reciprocal. Negative experiences can equally affect biological function, for example hormone balance can be affected by stress. Anisman and Zacharko supported this in a study demonstrating that not all those with a genetic family history of depression go on to become depressed individuals (Anisman and Zacharko, 1982). Similarly, there are those who suffer psychological disorders where no gentic link is evident.

In conclusion, different approaches attempt to understand psychological events and all have strengths and weaknesses. Advances in technology allow the brain to be investigated in exciting and illuminating ways producing clear material evidence which highlights how biological systems work to maintain stability. When function is impaired, we can see links between changes in processes and alteration in behaviour. However, it is not useful to consider a dichotomy between how we function and our social world. This ignores our experiences and meanings and, therefore, provides an incomplete picture of possible influences contributing to psychological events. Furthermore, this approach is fixed by our biology and make-up which limits treatment options to restoration of function alone.

A contrasting viewpoint, which is less extreme and more diverse, claims biology is not a single deterministic factor, but contributes to greater psychological insight when considered as a conjunct to social and psychological events. Analysis is then at a higher level which is more encompassing because it adds a qualitatitive element. This can, however, introduce difficulties for the researcher, with data less clear.

The development and impact of further neurophysiological investigation methods can not be predicted. Nevertheless, it seems insufficient to rely on a fixed reductionist approach alone for greater psychological understanding. Integrating biology ad psychology provides evidence that this has the potential to improve treatment of the individual based on deeper insight of what it tells us about ourselves, highlighting fluidity and offering the opportunity, therefore, to change.


Anisman, H. and Zacharko, R.M. (1982) ‘Depression: the predisposing influences of stress’, The Behavioural and Brain Sciences, vol.5, pp.89-137.

Crick, F. (1996) The Astonishing Hypothesis: The Scientific Search for the Soul, London, Simopn and Schuster.

Damasio, A.R. (1996) Discartes’ Error: Emotion, Reason and the Human Brain, London, Papermac.

Finlay, L., Kaye, H., Kynan, S. and Thomson, A. (2002) Workbook,DSE212, Exploring Psychology Milton Keynes, The Open University.

Macmillan, M.B.(1986) ‘A wonderful journey through skull and brains: The travels of Mr Gage’s tamping iron’, Brain and Cognition, vol.5, pp.67-107.

Toates, F. (2002), ‘Biological processes and psychological explanation’ in S.Miell, D., Phoenix, A. and Thomas, K. (eds.), Mapping Psychology, Milton Keynes, The Open University.

Wall, P.D. (1993) ‘Pain and the placebo response’, in Bock, G.R. and Marsh, J. (eds) Experimental and Theoretical Studies of Consciousness, Chichester, New York, Wiley.


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