Genetics and behaviour

Genetics and Their Influence on Behaviour

Genetics refer to the study of genes and their roles in inheritance - the way certain traits or conditions are passed down from one generation to another.
Humans have about 20,000-25,000 genes which are made up of DNA. It is this DNA that dictates how we develop and function.
Your genes, located in the chromosomes you inherit from your parents, contain the code for building and maintaining your body, including your brain - so they can have a profound influence on your behaviour.

Twin Studies and Behaviour

Twin studies are often used by psychologists studying the nature versus nurture question. Identical twins share 100% of their genes, while non-identical twins share about 50% of their genes, the same as any other siblings.
Twin studies can be very helpful in determining the strength of genetic influences on behaviour. If identical twins are more likely to share a behavioural trait than non-identical twins, this suggests the behaviour has a genetic basis.

Genes and Mental Health

It’s important to remember that having a certain gene, or set of genes, doesn’t necessarily mean you will develop particular behaviours or mental health conditions. It merely means you may be more susceptible to these conditions.
For example, a number of genes have been linked to the development of schizophrenia, but having these genes doesn’t guarantee someone will develop the disease. Environmental factors such as substance abuse, stress, or traumatic events are often necessary to trigger the expression of these genes.
Likewise, just because someone has the genes associated with intelligence, this doesn’t guarantee they’ll be a genius. Other factors such as upbringing, education, and environmental influences also play a critical role.

Impact of Epigenetics on Behaviour

Epigenetics is a more recent branch of genetics that’s helping us understand more about behaviour. It explores changes that occur in gene expression that does not involve alterations to the underlying DNA sequence.
Epigenetic changes can switch genes on or off and determine which proteins are transcribed. They can be influenced by various factors such as age, environment/lifestyle, and disease state.
Epigenetic changes can be passed down to future generations and could explain how environments and lifestyle can influence the behaviour of offspring. For example, studies have found smoking or undernutrition during pregnancy can lead to increased health risks in future generations.

Use this summary as part of your revision for the Biological approach to understanding behaviour, focusing specifically on the potential influence of genetics and epigenetics on behaviour.