Biological Approach

Question 1

Strength of twin studies: Supporting evidence for genetic explanation

Answer 1

A strength of genetic explanations of human behaviour is the supporting evidence from twin studies. For example, McGuffin conducted a twin study on depression and found concordance rates of 46% for MZ twins and 20% for DZ twins. This suggests depression is at least partly genetic since twins who are genetically
identical were over twice as likely to both have the disorder than for non-identical twins. Evidence supporting the role of genes therefore supports the idea that psychological characteristics are determined by our biology.

Question 2

Limitation of Twin Studies
Nature and nurture cannot be easily separated

Answer 2

separated: A limitation of genetic explanations of human behaviour is that research often involves the use of twin studies. Since identical twins
are usually raised in the same environment, it is impossible to disentangle the role of inherited and environmental influences. For example, if a high concordance rate is obtained, we cannot be sure whether this degree of similarity is due to the fact they are genetically
identical or the fact they are treated similarly. This is a limitation as methodological issues such as these affect the validity of research into biological factors.

Question 3

+-Practical application of biochemical explanations:

Answer 3

A strength of understanding about
biochemical processes in the brain is that this has enabled the development of psychoactive
drugs that alter levels of these biochemicals. For example, knowing that depressed patients have lower levels of serotonin has led to the development of antidepressants that increase levels of serotonin and can decrease depressive symptoms. This practical application shows
how understanding biology can help improve people’s lives

Question 4

Diathesis-stress model:

Answer 4

Rather than focus on a purely biological explanation (nature) to
human behaviour it may be beneficial to use the diathesis stress model which looks at the interaction between both nature and nurture (environment). According to this model certain genes leave the individual more vulnerable to developing psychological disorders such as depression. Whether an individual actually does develop these disorders is influenced by the
interaction with an environmental factor (stressor). This suggests that human behaviour cannot entirely be genetic in origin, at least not in all cases. This suggests it may be more
beneficial to look at the complex interaction between genetics and the environment in order to fully understand human behaviour.