The Biological Approach Flashcards
Define the Biological Approach
An approach to psychology that emphasises the importance of physical bodily processes (e.g. genetic inheritance + neural function) on behaviour
When was the Biological Approach developed?
1980s
Why was the Biological Approach developed?
New advances in tech made a scientific, more biologically based approach to psychology possible
Who were key figures in the Biological Approach?
- Darwin
What are the key assumptions of the Biological Approach?
- All behaviour has a physiological basis (stemming from aspects such as: genetics, neurochemistry, biological structures)
- There is a difference between genotype + phenotype, due to the importance of interaction between biology + the environment
- Evolution can gradually change patterns of human behaviour
What are the three main methods used in the Biological Approach to investigate the genetic basis of behaviour?
- Twin studies
- Family studies
- Gene mapping
How can twin studies be used to investigate the genetic basis of behaviour?
- Compare concordance rate of MZ + DZ twins
- If behaviour is solely based on genetics, concordance rate will be 100% in MZ twins + 50% in DZ twins
- If behaviour is solely based on environment, concordance rate could be as low as 0% between both sets of twins
Define concordance rate
Extent to which two genetically related individuals share the same behaviour, disorder or characteristics
Define MZ twins
Monozygotic Twins
- Identical twins
- From same egg
- Share 100% of genes
Define DZ twins
Dizygotic Twins
- Non-identical twins
- From diff egg
- Share 50% of genes
Give an example of how the importance of genetics has been investigated using twin studies
OCD
- Miguel et al
- Concordance rate of MZ twins: 53-57%
- Concordance rate of DZ twins: 22-46%
- Concluded OCD is partially caused by genetic inheritance
How can family studies be used to investigate the genetic basis of behaviour?
- Compare concordance rates of first degree + second degree relatives
- The higher the concordance rate, the greater the influence of genes on behaviour
What are first degree relatives?
- Relatives that share 50% of genes
- Parent, child, full sibling
What are second degree relatives?
- Relatives that share 25% of genes
- Other relatives
Give an example of how family studies have been used to investigate the genetic basis of behaviour
OCD
- Nestadt et al
- First degree relatives of OCD sufferers: 11.7% chance of OCD
- Second degree relatives of OCD sufferers: 2.7% chance of OCD
How can gene mapping be used to investigate the genetic basis of behaviour?
Map genes to show likelihood of certain behavioural disorders, indicating role of genes in causing these behaviours
What three biological aspects affect behaviour?
- Genes
- Neurochemicals
- Biological structures
How is our behaviour thought to be affected by genes? .
- Some characteristics (physical + psychological/behavioural) are inherited through genes, as genes code for them
- Mutations in genes may affect behaviour by causing a disorder
How many genes do we have?
20,000 -> 25,000
What do genes make up?
Chromosomes
How many chromosomes do we have?
23
Give an example of a psychological/behavioural characteristic that may be coded by a gene
Intelligence
Give an example of a gene mutation that affects behaviour by causing a disorder
XYY = Aggression
Outline how characteristics are inherited through genes
- One gene inherited from each parent
- Dominant gene expressed (unless both genes recessive)
- This expressed gene determines a characteristic, affecting behaviour
Define neurochemistry
Study of chemical processes in the brain/nervous system
How is our behaviour thought to be affected by neurochemistry?
- Some behaviours are dependent on chemical transmissions of neurotransmitters in the brain
- If there is too much or too little of certain neurotransmitters, this can affect behaviour + cause disorders
What are the two types of neurotransmitters? What does each type do?
- Excitatory = trigger + stimulate brain into action
- Inhibitory = calm + balance brain
Where are neurotransmitters released?
At the end of a neurone, across synapses
What are neurotransmitters?
Chemicals that deliver messages - affecting behaviour
How can biological structures affect behaviour?
Different parts of the brain have different roles in behaviour
- Size/innate activity of an area can affect behaviour
- Damage to an area can affect behaviour
What are the three key areas of the brain? What is each responsible for?
- Cerebrum (main part of brain - thinking etc)
- Cerebellum (voluntary motor movements)
- Medulla oblongata (automatic functions + connection to spine)
What are the four cerebral lobes? What is each responsible for?
- Frontal lobe (Speech, higher cognitive functions)
- Temporal lobe (Processing auditory info)
- Parietal lobe (Processing sensory info)
- Occipital lobe (Processing visual info)
What methods are used to investigate the role of biological structures in behaviour?
- Brain scans (fMRIs, PETs, EEGs, ERPs)
- Post mortems
- Lesion case studies
How can brain scans be used to investigate the basis of behaviour?
Brain scanning techniques include: fMRIs, PETs, EEGs, ERPs
- fMRIs: use radio waves to measure brain activity during a task
- PETs: creates 3D image of body + uses radioactive drug to see which areas (e.g. of brain) are active
- EEGs: electrodes on skull cap record electrical activity of the brain
- ERPs: statistically analyse EEG data to isolate brain activity in response to a particular event
Give an example of brain scans being used to study behaviour
Raine et al
- Examined PET scans of violent criminals
- Found reduced activity in frontal lobe
- This reduced activity here has become associated with aggression
How can post mortems be used to investigate the basis of behaviour?
Brain analysed after death to determine whether certain observed behaviours during a person’s lifetime can be linked to structural abnormalities in the brain
(Usually done on person with rare disorder - e.g. HM - who is then compared to the ‘normal’ brain structure)
How can case studies be used to investigate the basis of behaviour?
Case studies (detailed investigation of an individual/small group) with brain damage are compared to control group without, to determine role of certain areas in certain behaviours
Give an example of a case study being used to investigate behaviour
Phineas Gage
- Worked on US railroad in 1840s
- Explosion, 3cm diameter metal bar through skull, damaged left frontal lobe
- Big behavioural change: more angry + foul mouthed
- Suggested role of frontal in lobes in personality + aggression
Define genotype
Genetic code an individual possesses
Define phenotype
Observable characteristics an individual possesses, due to an interaction between genotype + environment
Define diathesis-stress model
Theory that behaviour is caused by…
Biological predisposition: ‘diathesis’
Environmental trigger: ‘stressor’
Why might MZ twins have a different phenotype?
Despite sharing 100% of their genes, they may be affected by different environments
Give an example of the diathesis stress model in action
PKU (rare genetic disorder)
- Diathesis can be detected using a heel prick test on babies
- If environment is changed (strict diet) baby ca develop normally
- If they have a normal diet, this acts as a stressor + causes learning difficulties
Who identified the process of evolution?
Darwin (19th C)
Define evolution
Changes in inherited characteristics in a biological population over successive generations
What process causes evolution to occur?
Natural selection
- Genes that best equip individuals for survival become more prominent in a population, because individuals with these genes have a greater chance of surviving longer (survival of the fittest) + reproducing more
How does evolution change a species’ behaviour?
Changes population’s genes, therefore characteristics, therefore behaviour
Give 2 positive evaluation points for the biological approach
Methodology is scientific
- Research often takes place in highly controlled lab settings
- Methods are often objective + respected in the scientific field (e.g. PET scans)
- Increases the internal validity + reliability of the findings, meaning they are more respected and valuable for making nomothetic laws
Real world application
- Many treatments have arisen due to knowledge from the Biological Approach
- E.g. Drug treatments like SSRIs for OCD have arisen through this approaches’ investigation of neurotransmitters
- This approach has helped the medical profession and the lives of suffering individuals
Give 2 negative evaluation points for the Biological Approach
Reductionist
- The approach reduces behaviour down to its simple biological/physiological components
- This may be deemed ‘Biologically Reductionist’
- The approach doesn’t consider the impact of factors such as human desire on behaviour, treating everyone as identical, made up of the same basic components
- Therefore, the approach may be seen as less valid, ignoring some causes of behaviour
Deterministic
- The approach suggests behaviour is governed by internal physiological causes
- This suggests humans have no free will/control over their behaviour, it is instead pre-determined at birth by their genes, neurones + structures
- This is pessimistic, not encouraging humans that they can make a change and dictate their own future
- This may act as an excuse for bad behaviour which has implications for the legal system (e.g. blaming murder on an aggression gene)
- Therefore, the deterministic nature of this approach has negative implications for the individual + wider society
