Describe how genes might influence social behaviours.

Genes can influence social behaviours by affecting the brain's structure and function, which in turn shape our responses to social stimuli.

Genes are the basic units of heredity, carrying the instructions for the growth, development, functioning, and reproduction of all known organisms. They are made up of DNA and are responsible for the physical and behavioural characteristics of an individual. In the context of social behaviours, genes can play a significant role.

One way genes might influence social behaviours is through their impact on the brain's structure and function. For instance, certain genes are known to influence the development and functioning of the brain's reward system, which plays a crucial role in social interaction. Variations in these genes can lead to differences in how individuals respond to social stimuli, such as the pleasure derived from social interaction or the distress caused by social rejection.

Moreover, genes can also influence the production and function of neurotransmitters, the chemical messengers that transmit signals across a synapse from one neuron to another. For example, the gene that codes for the serotonin transporter, a protein that helps regulate the amount of serotonin available in the brain, has been linked to social anxiety and depression. Individuals with certain variations of this gene may be more prone to these conditions, which can in turn affect their social behaviours.

In addition, genes can interact with environmental factors to shape social behaviours. This is known as gene-environment interaction. For instance, individuals with a certain genetic predisposition may be more susceptible to the effects of social stress, which can in turn influence their social behaviours.

However, it's important to note that genes are not the sole determinants of social behaviours. While they can predispose individuals to certain behaviours, the expression of these behaviours is often influenced by a complex interplay of genetic, environmental, and personal factors. This is known as the nature-nurture debate in psychology.

In conclusion, while our understanding of the genetic basis of social behaviours is still evolving, it's clear that genes can play a significant role in shaping these behaviours. However, they are just one piece of the puzzle, and their effects are often modulated by a host of other factors.