Biological Approach
| For this section you need to be able to:
a Define the biological approach showing understanding that it is about the influence and impact of genes and the nervous system on individual differences. b Define and use psychological terminology appropriately and accurately including the terms: i central nervous system (CNS) |
Biological psychology is concerned with the study of how our physiology is involved in the control of our behaviour. It looks at different areas such as development, evolution, genetics and physiology. It believes that studying the brain can help us understand the psychological processes that effect our behaviour.
Biological Psychology combines psychology with biology to study the biological origins of human behaviour. The approach became very influential in the 1950’s following the publication of a book by D. O. Hebb called ‘The Organization of Behaviour’ which claimed that there was evidence to suggest that all of our behaviour could be explained by simple chemical impulses and genetics.
Biological psychologists have made some huge contributions to the study of psychology since they first started studying people. They have created brain scanning and imaging techniques to allow us to see living brains, they have developed surgical methods to disable parts of the brain to see what effect this has on abnormal behaviour, and they have looked extensively at genetic research to try to map out human behaviour from birth. By understanding the workings of the brain the approach has developed chemotherapy for clinical conditions such as schizophrenia and depression. This will be studied in more detail at A2 (unit 4)
This approach is very scientific and takes a reductionist view on all human behaviour, explaining everything we do by the smallest units possible – our biological make-up.
This approach states that to understand psychological functioning we need first to understand physiological aspects of the organism. It assumes that humans are a biological species with bodies that are comparable in some respects to those of other species.
Our genetic makeup (which shapes our physiology) is shared to some extent, across all species. The more genes we have in common with a species, then the more similar we are.
This means that it is appropriate to conduct research on these species and apply this knowledge to humans. In the nature nurture debate this approach is largely on the side of nature.
The Central Nervous System (CNS), consists of the brain and the spinal chord and controls much of our behaviour by passing electrical impulses around the body through nerve fibres made up of tracts of neurones.
Neurones are tiny nerve cells that communicate messages in the brain and around the rest of the body through impulses passed around the nervous system via synapses.
A synapse is a junction between 2 neurones where messages are passed from one neurone to another. These messages are passed through neurotransmitters which move from the terminal button of one neurone, to the receptors on the dendrite of another neurone.
Neurotransmitters are chemicals that are released by neurones into the synaptic gap. Receptors (protein molecules situated on the membrane of the neurone) on adjacent neurones allow the neurotransmitter to attach to them if the neurotransmitter is the right shape to fit that particular receptor. This then changes the chemical makeup of the neurone and therefore its voltage causing an electric charge to pass down the axon of the neurone (called an action potential). When the charge gets to the terminal buttons at the bottom of the axon it causes neurotransmitters held within that neurone to be released into the synapse.
Genes are made up of DNA (deoxyribonucleic acid) which is involved in controlling how the body develops. Genes are contained on chromosomes, and we inherit 23 chromosomes from each of our parents. This may account for similarities shared between family members as we will share some of our genetic make-up with them. The closer the relationship, the more genes you will share in common.
Hormones are chemicals that are secreted into the blood and transported around the body to effect various sites and functions. All developing foetuses have the same undeveloped sex organs until 6 weeks into the pregnancy. At this point, if there is a Y chromosome, a chemical (DHT) is released that leads to the development of testes. If there is no Y chromosome, the sex organs develop by default into ovaries.
Once these sex organs have developed, they secrete sex hormones that will determine how the sex organs fully develop. The presence of testes means that anti-Müllerian hormone will prevent the development of female sex organs, and the production of androgens will encourage the development of a penis. The absence of these sex hormones results in female sex organs developing.
The brain is made up of 2 hemispheres that appear to be symmetrical . However it is known that each hemisphere is responsible for different functions. Lateralisation is about how much each hemisphere performs different functions from the other. This is known as functional asymmetry
In males, there is more left hemisphere activity during linguistic tasks, but in females there is usually bilateral brain activity during the same tasks. During spatial tasks, males show high levels of activity in the right hemisphere; whilst in females we are again more likely to see bilateral brain activity. The corpus callosum is the connecting tissue between the 2 hemispheres. Studies show that this is thicker in females and perhaps this explains why female brains are more bilateral, because the two hemispheres communicate more efficiently.