With reference to relevant research studies, to what extent does genetic inheritance influence behaviour?
Make sure you have a copy of the key questions, learning targets and glossary for this topic.
It is important to note that this GLT is asking that you determine for yourself how much of our behaviour is a result of genetics, or the environment. As you look at the empirical data, you will soon realise that it is a combination of both factors, and so you have to use this evidence to explain just how much is genetic (i.e. passed on from our parents).
Behaviours and Research:
- Intelligence (Minnesota Twin Study; Bouchard and McGue; other twin and adoption studies)
- Homosexuality (Bailley and Pillard)
- Schizophrenia (Heston)
- Psychological Disorders (Bulimia and PTSD)
- PKU and Huntingon’s disease
- if you are struggling in an exam to remember these details, you could also discuss evolutionary explanations of why some traits are attractive, as long as you are making clear links to genetics and inheritance
It is also important that you understand in detail how twin and adoption studies are used to study genetics. You need to understand what is meant by MZT (Monozygotic Together), MZA (Monozygotic Apart), DZT (Dizygotic Together) and DZA (Dyzogtic Apart). You will find this information on pages 58-61 of the Pearson Textbook. The terms concordance rate and heritability are also important for you to understand. The concordance rate is similar to correlation. It means how likely is it if one twin exhibits a certain behaviour, is the other twin likely to exhibit the same behavior.
For example, if you have 4 sets of identical twins (i.e. 8 participants), and two sets of twins are homosexual (i.e. 4 of the participants) and the other two sets only one of the twins is homosexual, you would say there is a 50% concordance rate.
In the Course Companion on pages 54-56, you will find information on a range of different twin and adoption studies that you will be able to use for this topic. Some are quite interesting – such as the studies that show how a person’s intelligence can be influenced by the socio-economic status that they are adopted in to.
There are details on this study on page 60 of the Pearson Textbook. The results are quite straightforward. They show a strong correlation between genetics and the development of schizophrenia. It is important, however, to analyse these results critically.
The results of this study on page 60 of the Pearson Textbook can be used to show exactly how behaviour can be both environmental and genetic.