Research methods of the Biological approach
- Created by: CharlotteCollins4
- Created on: 17-05-15 12:40
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- Research methods in the biological approach
- Twin studies
- Used to examine the role of genes on behaviour
- Identical twins share 100% of their genes
- These are called monozygotic twins (MZ)
- Even if they live together, MZ twins will have different experiences and environments to one another, even in the womb
- Have different fingerprints to one another
- Some genetic characteristics are triggered by the environment and so over time twins can become less identical
- Epigenetic modification is the term to describe this
- However some characteristics such as IQ can become more alike over time
- These are called monozygotic twins (MZ)
- Identical twins share 50% of their genes
- Dizygotic twins (DZ)
- Identical twins share 100% of their genes
- Aid the nature/ nurture debate
- Nature is based on our genes and what we are born with
- Nurture is what we experience as we develop from our environment
- Twins tend to share much of the same environment which makes them bad to study in everyday life
- Why adoption studies are so strong
- Here twins live in different environments and so we can examine the role of environment on behaviour
- Why adoption studies are so strong
- Twin studies compare MZ and DZ twins on certain characteristics
- If there are strong differences then the characteristics are said to be genetic
- When both sets of twins share a characteristic then there is said to be a concordance rate
- Twin studies are strong as there is no alternatives, there is no other way to share the exact same DNA as someone
- Most twins share the same environment and are treated simply as twins so there should be a lack of extraenous variables
- However MZ twins may be treated differently to DZ twins as they are identical
- No twins are exactly identical
- Used to examine the role of genes on behaviour
- Adoption studies
- Enables the role of environment to be examined
- Where a child is adopted and thus has a different environment to that of its biological family
- Environment is controlled which is a strength
- E.g a researcher examining whether schizophrenia is environment or genetically based would use this as the child would share the gene if it existed
- Similarities with their biological families will be due to genes
- Often family situations are matched so environments wouldn't have been that different to that of their biological families
- Adoption is an official process
- All adoptive families may be the same
- Adoption is an official process
- Developmental trends can be studied as the studies are longitudinal
- Twins reared apart
- Another form of adoption study
- MZ twins separated at birth
- Usually adopted
- Controls the similarity of environments
- A unique method
- Very few MZ twins have been reared apart
- Therefore it is hard to draw conclusions
- Often family members bring up the children
- Reared apart but as part of the same family
- Sometimes in these studies it can be hard to tell if the twins are MZ or DZ
- Unethical to deliberately raise twins apart
- PET scans
- Positron emission tomography
- 1) A radioactive transmitter is injected into the patient
- 2) This attaches to a chemical in the bloodstream, usually glucose
- 3) It travels to the brain through the bloodstream and to the areas where energy (glucose) is needed which are the sights of activity
- 4) A positron is given off that is in the tracer and this shows up as an area of activity
- Shows what areas of the brain are used for what function
- Shows blood flow to the brain
- Having the injection is invasive
- Unethical as uses radioactive material which could cause harm
- Could be psychologically harmful to people with claustrophobia
- More ethical as usually animals would be used using surgery for this purpose
- High validity
- Very reliable and easily repeatable
- It is hard to isolate certain areas of the brain
- Criticises the validity of PET scans
- MRI
- Magnetic resonance imaging
- 2) A strong magnetic field is passed over the area
- 3) A cross sectional image is created from this
- Images are affected by movement so the person has to keep very still
- Do not show activity to the same extent as PET scans
- Can measure blood flow
- 1) A dye (contrast medium) is injected into the body
- High validity
- More ethical than surgery but still invasive as uses an injection
- Replicable
- They are extremely noisy which can be distressing
- Limited knowledge can be obtained from these as they only measure body tissue
- Using animals in lab experiments
- 8% of research uses animals
- 90% on rodents and birds
- 5% on primates
- Mice have similar enough genes to humans and breed quickly
- different generations can be quickly and easily studied
- Most animals used are small and easy to handle
- Quite a few animals share similar brain patterns and functions
- Research can be useful for animals as well as humans
- E.g by understanding their anatomy zoos can care for them better
- More practical to use animals
- E.g animals age quicker than humans
- Extraneous variables such as diet can be monitored easier
- No animal is identical to a human
- These studies often don't take into account the complexity of real life
- Illness' and diseases have to be artificially created in animals, this isn't the same as developing them naturally
- Lack credibility
- Studies that can't be carried out on humans cane be carried out on animals
- We should improve our way of life by any means
- Advantageous new drugs can be developed
- Cause harm and so are unethical
- 8% of research uses animals
- Twin studies
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