The biological approach

• if we want to fully understand human behaviour we must look to biological structures and processes within the body, such as genes, neurochemistry and the nervous system.
• behaviour has a genetic and neurochemical basis

  behaviours are inherited in the same way as physical characteristics such as height or eye colour. for example, the 5HT1-D beta gene implicated in OCD.

  neurochemistry also explains behaviour, for example low levels of serotonin in OCD.
• from a biological perspective, the mind lives in the brain- meaning that all thoughts, feelings and behaviour ultimately have a physical basis.

  this is in contrast to the cognitive approach which sees the mind as separate from the brain.
• the use of twin studies to investigate the genetic basis of behaviour

  concordance rated between twins are calculated- the extent to which twins share the same characteristic.

  higher concordance rates among identical (monozygotic, MZ) twins than non-identical (dizygotic, DZ) twins is evidence of a genetic basis. for example, 68% of MZ twins both have OCD compared with 31% of SZ twins (nestadt et al.)
• difference between genotype and phenotype

  • a persons genotype is their actual genetic makeup
  • phenotype is the way that genes are expressed through physical behavioural and psychological characteristics
  • the expression of genotype (phenotype) is influenced by environmental factors.
  • For example, phenylketonuria (PKU) is a genetic disorder that can be prevented by a restricted diet.
  • this suggests that much of human behaviour depends on the interaction of nature and nurture.
• the theory of evolution is used by the biological approach to explain many aspects of behaviour

  • proposed by Charles Darwin
  • any genetically determined behaviour that enhances survival and reproduction will be passed on to future generations
  • such genes are described as adaptive and give the prossessor and their offspring advantages.
  • for instance, attachment behaviours in newborns promote survival and are therefore adaptive and naturally selective.
• strength of the biological approach: its use of scientific methods of investigation

  in order to investigate the genetic and biological basis of behaviour, the biological approach makes use of a range of precise and highly scientific methods. these include scanning techniques (e.g. fMRIs) and drug trials. it is possible to accurately measure biological and neural processes in ways that are not open to bias. this means that the biological approach is based on reliable data.
• strength of the biological approach: real-life application

  increased understanding of biochemical processes in the brain has led to the development of psychoactive drugs that treat serious mental disorders, such as depression. although these drugs are nit effective for all patients, they have revolutionised treatment for many. this is a strength of the approach because it means that sufferers are bale to live a relatively normal life, rather than in hospital.
• limitation of the biological approach: based on a determinist view of behaviour

  the biological approach is determinist in that it sees human behaviour as governed by internal, biological causes over which we have no control. however, this is at odds with the legal system which sees offenders as responsible for their actions. the discovery of a 'criminal gene' may complicate this principle. such research may have (possibly negative) implications for wider society as criminals may be able to excuse their behaviour.