AQA A-LEVEL: Approaches - The Biological Approach

THE BIOLOGICAL APPROACH

ASSUMPTION is that all behaviour is driven by physiological factors like genetics, biological structures and neurochemistry. Focuses on NATURE shaping our behaviour.

EVOLUTION AND BEHAVIOUR (suggested by Charles Darwin)

  • Evolution - Gradual change within a species over time in response to environmental pressures
  • Natural Selection - Inherited characteristics which enhance survival, passed on to the next generation
  • Adaption - A behaviour or trait which increases successes or survival and reproduction
  • Survival of the Fittest - Only those best suited to the environment will survive and reproduce
  • Sexual Selection - When individuals possess features that make them attractive to the opposite sex and helps them compete with the same sex for mates, increases reproductive success
Phobias such as arachnophobia can be seen to be adaptive as it increases survival. Living as a social species offers advantages, survival would decrease if we lived and hunted in isolation.

GENES AND BEHAVIOUR

  • Genotype - The genetic constitution of an individual. Variation in humans (0.1%) cand cause large variations across species. We are 98% similar to chimpanzees
  • Phenotype - Result of interactions between inherited characteristics and the environment e.g. Flamingo feathers are originally white but turn pink due to the type of fish they eat 
  • Males have an XY chromosome and have testosterone as their hormone whereas females have an XX chromosome and have oestrogen as their chromosome
    • SRY trigger triggers the gene that will make the foetus develop testes if the trigger does not occur ovaries are developed instead
  • DEPRESSION IN TWIN STUDIES
    • MZ twins (100% DNA) compared with DZ twins (50% DNA), both grew up in the same environment and measured their concordance rate to see if they had the same traits
    • MZ 49%, DZ 17%, Siblings 9%

BIOLOGICAL STRUCTURES / NEUROANATOMY

  • Looking at the relationship of areas of the brain and their functions, difficult to do due to brain plasticity. Done via case studies of brain damaged pt's psychosurgery or brain scanning devices.
  • BROCA 1861 was able to identify areas of their brains and functions.
  • WOOLLETT AND MAGUIRE 2011 - looked at the idea memory is localised to the hippocampus. Taxi driver applicants in London have to remember a lot of routes, Maguire did brain scans on the drivers.
    • PTs who successfully did memory tasks had a large hippocampus compared tp control pts
    • But memory systems are difficult to localise a specific structure for it as other components interlink
  • RAINE ET AL 1997 - Looked at PET scans of violent criminals who pleaded NGRI compared to their control group of matched pairs
    • Results showed there was reduced activity in the frontal lobes, he also looked at the Limbic System and the amygdala which is the emotional part of the brain. He also identified the Hypothalamus, the corpus callosum and the prefrontal cortex.

NEUROCHEMISTRY AND BEHAVIOUR 

  • Behaviours or mental disorders may be genetically inherited due to neurochemistry
  • Neurochemistry - Chemical processes in the brain
  • Neurotransmitters - Chemicals released from neurones which allow them to communicate and relay messages. Neurotransmitters have corresponding neurones
  • Excitatory - Increases the pace of brain communication
  • Inhibitory - Decreases the pace of brain communication
  • Neurochemistry can be influenced by psychoactive drugs

GABA - Inhibits neurones, blocks brain signals. Helps ADHD reduces symptoms of PMS
DOPAMINE - Precursor of adrenaline and controls brains reward and pleasure centres
SEROTONIN - Inhibits receiving neurones, a deficit of serotonin leads to depression
NORADRENALINE - Injected for bad blood pressure, fight or flight chemical
ACT (acetylcholine) - Acts on PNS, found in nervous system 

EVALUATION

PRACTICAL APPLICATIONS for treating mental health
  • Effective drug treatments which are quick acting e.g. Anti-psychotics - help 85% of schiz pts 
NOT GENERALISABLE AS RESEARCH COMES FROM ANIMAL RESEARCH
  • Evolutionary discontinuity, there are qualitative differences. Animal research can't generalise to humans effectively. Humans have LAD (language acquisition device) which no other animals have which make humans unique 
BIO APPROACH IS HIGHLY SCIENTIFIC
  • Uses objective and falsifiable methods e.g. NT levels can be measured objectively via cerebral spinal fluid as well as examining urine. Biochemical actions are trustworthy and reliable. 
RESEARCH EVIDENCE FROM HM
  • HM had epilepsy, damaged part of brain removed (within temporal lobe + hippocampus) in an operation. Epilepsy cured, anterograde amnesia occurred, LT no functional as he couldn't learn new material. Shows hippocampus is involved in the transfer of memories.
HM RESEARCH HAS METHODOLOGICAL ISSUES
  • HM was the only pt, we don't know if these effects would occur in all individuals with damage to the hippocampus. Also, androcentric, female brains may differ. Not generalizable.

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