Biological psychology: the basics
- Physiology is important in explaining human behaviour; how the brain, nervous system and hormones operate, and how any changes in the structure and function of organs and chemicals in our body affect our behaviour
- Heritability is important; we must understand the role that genes play in determining our behaviour, e.g. is intelligence inherited?
- Comparative psychology; animals are studied and compared to humans to help us understand more about human behaviour
Assumptions of the biological approach
Biological psychologists assume that behaviour and experiences are caused by activity in the nervous system of the body. The nervous system is made up of many neurones that pass messages via electrochemical impulses – it is particularly this activity in the brain that biopsychologists are interested in. The development of the brain is determined (at least partly) by the genes a person inherits, therefore behaviour may be influenced by genetic factors. Finally, because the genes we inherit are the result of evolution, many biopsychologists think that behavioural and psychological characteristics may have evolutionary explanations.
How do biopsychologists explain human behaviour?
1. Brain function as an explanation of behaviour
The brain can be subdivided into different areas and biopsychological explanations often focus on which brain areas are responsible for which types of thinking or behaviour.
For example, language in humans is thought to be governed by two areas of the cerebral cortex; Broca’s area, which controls the production of speech and Wernicke’s area, which controls the comprehension of speech. These ‘speech centres’ are connected to a variety of other brain areas, including those involved in thinking and in auditory working memory.
2. The role of genetic influences on behaviour
For example, it is widely believed by biopsychologists that schizophrenia (a psychological disorder involving a range of symptoms including hallucinations, delusions and disorganised thinking and speech) is at least partly the result of inheriting a faulty gene or genes. These genes are thought to influence the development of the nervous system, making it vulnerable to malfunctioning in certain ways that produce the symptoms of the disorder.
3. Chemical processes in the brain e.g. neurotransmitters and hormones could explain behaviour
The brain relies on a large number of chemicals (called neurotransmitters and hormones) to send signals between neurones. Too much or too little of any of these chemicals can result in over- or under-activity in various parts of the brain, which results in changes to thinking, feeling and behaviour.
For example, some researchers have shown how behaviour can be affected by altered levels of sex hormones. Increased testosterone leads to increased risk-taking and aggression, whereas increased oxytocin leads to increased nurturing and social responsiveness.
Neurotransmitters can play an important role in regulating our mood; an imbalance of different neurotransmitters has been linked to various psychological disorders. For example high levels of the neurotransmitter dopamine have been linked to schizophrenia, and low levels of serotonin have been linked to depression.