Biological Approach

• Assumptions


  - suggests everything psychological is first biological, so to fully understand human behaviour, we must look at biological structures and processes in the body, such as genes, neurotransmitters and nervous system

  - mind lives in the brain - all thoughts, feelings and behaviour have a physical basis

  - contrasts the cognitive approach that sees mental processes of the mind as being separate from physical brain
• Genes


  make up chromosomes and consist of DNA which codes the physical features of an organism e.g. eye colour, hair colour, height, and the psychological features e.g. mental disorders, intelligence
• Hormones


  chemical substances that act like messenger molecules in the body.

  after being made in one part of the body , they travel to other pats of the body where they help control how cells + organs work
• Neural


  Brain
• Neurochemistry


  study of chemical processes which takes place in the nervous system.

  much of our thought and behaviour relies of chemical transmission in the brain

  occurs using neurotransmitters - body's chemical messengers
• Excitatory neurotransmitter


  trigger nerve impulses in receiving neurone and stimulate the brain into action.

  e.g. dopamine is associated with pleasure and motivation and has been implicated in addictive behaviour e.g. smoking and psychological disorders e.g. SZ
• Inhibitory neurotransmitter


  inhibit nerve impulses in order to calm the brain and balance mood.

  e.g. serotonin, which has wide ranging effects and been implicated in a range of behaviours including sleep memory, emotion aggression and appetite as well as psychological disorders such as anorexia nervosa, depression and OCD
• Gene mapping


  studies identify particular genes and show they're more likely to be present in individuals with a certain disorder than those without the disorder
• Heritability coefficient


  used to quantify the genetic or biological basis of a certain characteristic

  e.g. IQ have a heritability coefficient of 0.5 so the influence of genetics and environment are equal
• Family studies


  1st degree relatives share ~50% of their genes

  2nd degree relatives share ~25% of genes

  to investigate the role of inheritance in a characteristic/behaviour/disorder, studies are carried out that compare the rate for the disorder in those who are related to already diagnosed cases, with those who are related to controls
• Twin Studies


  offer another way of establishing genetic links, by comparing the differences in concordance rates for identical (MZ) and non-identical (DZ)

  MZ twins share 100% of genes

  DZ twins share 50% of genes

  if behaviour/characteristic was solely due to genetics then we would expect the concordance rate to be 100%
• Nestadt et al


  1st degree relatives of OCD sufferers have an 11.7% chance of developing OCD compared to a 2.7% chance in general population

  genetic basis for OCD as parents pass on vulnerability to that disorder to their offspring -> increasing risk
• McGuffin et al


  found the concordance rates for major depressive disorder in MZ twins was 46% and DZ twins was 20%
• Genotype


  collection of all genes within each cell of an individual

  individual's genetic makeup -> occurs at conception

  provides genetic code for an individual
• Phenotype


  behaviour + physical structure of an individual arising from an interaction between their genotype + environment

  product of what happens when genotype interacts with environment

  physical characteristics - height, genotype dictates the height
• Influence of biological structures

  largest part of the brain is the cerebrum - split into 2 halves with each hemisphere further divided into 4 different parts

  Frontal Lobe -> thinking, planning, STM

  Temporal Lobe -> memories

  Parietal Lobes -> touch, smell, taste

  Occipital Lobes -> visual activity
• Case Studies


  research method that involves a very detailed look into background of 1 person or small group
• Phineas Gage


  experienced an unexpected explosion which resulted in a metal bar going through his skull and brain

  despite severity of accident he survived and showed little intellectual impairment continuing to function relatively normally

  showed marked changes to his personality becoming angry and foul mouthed
• HM (Scoville and Milner)


  undergone surgery for epilepsy in which his hippocampus was removed.

  HM was unable to put any info into his LTM after surgery yet his STM was completely normal

  resulting impairment implies the hippocampus plays an important role in memory, particularly the transfer of info from STM to LTM

  - HM could no longer form new memories - anterograde amensia

  - lost memory for events that happened after his surgery

  - HM also suffered some retrograde amnesia of events before surgery
• Woollett and Maguire - supporting evidence for hippocampus and LTM

  become a London taxi driver -> pass a test 'The Knowledge'

  79 taxi drivers, 31 non-taxi drivers

  brains were scanned when starting the test-studying

  studying for test enlarged posterior hippocampus - area associated with spatial memory but only in trainees who passed

  similar enlargement didn't occur in drivers who didn't pass the test
• Evolution and Behaviour


  150,000yrs ago - ancestors were hunter-gatherers struggling to survive in hostile environments

  modern humans have retained some of these behavioural patterns from hunter-gatherer era

  Darwin identified 2 mechanisms which gradual changes to species could take place, these are when environmental resources are limited, and animals/humans compete for food, mates and shelter

  Darwin initially puzzled by structures such as peacock's long tail, which appeared to convey little way of survival advantage
• Evolution


  changes in inherited characteristics in a biological population over successive generations
• Example - Attachment


  Bowlby's evolutionary approach to attachment suggests attachment is innate

  critical period argues for our distant ancestors it would have been vital for infants to become attached as soon as possible and this is evidenced in young monkeys who cling to their mothers

  Bowlby argues human infants seek proximity and develop one strong emotional bond with the mother early on during a critical period to meet the biological needs of the infant and aid infant's survival
• Weakness - determinist view of behaviour


  biological approach is determinist as it suggests human behaviour is governed by internal, biological causes over which we have no control

  has implications for legal system and wider society

  one of the rules of law is criminals are seen as legally and morally responsible for their actions

  recent discovery of a gene for aggression may complicate this principle as this info could be used as part of the defence in the courtroom as justification for criminals' behaviour
• Weakness - biological approach is reductionist


  can be argued the biological approach is reductionist.

  it reduces complex behaviour down to simple components e.g. genes or neurotransmitters

  means all other possible influences on behaviour are ignored.

  e.g. role of learning through conditioning or modelling, and influence of cognition and emotion on behaviour

  full picture of human behaviour requires a study of both biological and environmental influences
• Strength - real-life applications


  insights from genetics and biochemistry provide important explanations of causes of psychological disorders, including OCD, depression and phobias

  led to practical applications in form of drug treatments for these disorders which are effective and quick-acting

  e.g. SSRIs, increase serotonin levels, have helped to manage the symptoms of depression and OCD, as research has indicated that patients with these disorders have low levels of serotonin in brain

  Strength - biological approach as it means the sufferers are able to manage their condition and live a relatively normal life, rather than remain in hospital
• Weakness - causal conclusions


  biological approach offers explanations for mental illness in terms of action of neurotransmitters

  evidence for this relationship comes from studies show a particular drug reduces symptoms of disorder thus it's assumed this neurotransmitter causes the disorder as the drug is effective.

  Weakness - biological approach as discovering an association between 2 factors doesn't mean that one is a cause
• Strength - scientific methods of investigation

  in order to investigate genetic and biological basis of behaviour, the biological approach makes use of a range of precise and scientific methods

  experimental studies take place in highly controlled environments so other researchers are able to replicate research studies under same experimental conditions, adding to the validity of original findings if they can be reproduced

  studies include brain scanning techniques family and twin studies and drug trials

  due to recent technological advancements it's now possible to accurately measure biological and neural processes in ways that aren't open to bias