Biological

• Biological Approach

  • combines psych and bio to provide physiological explanations for human behaviour
  • tries to explain how we think, feel and behave in terms of physical factors within the body
• Assumptions

  • everything physiological is at first biological
  • investigates how biological structures and processes within the body impact on behaviour
  • human behaviour has psychological cause which may be genetically/behaviourally altered
  • genes influence individual psychological differences between people
  • evolutionary psychology considers genetic influences in common behaviours
  • study the brain, CNS and other biological systems like hormones and chemicals acting on brain
  • all thoughts, feelings and behaviour have physical basis - mental processes of mind are separate from brain
• Genes

  • genetic information carried by DNA in chromosomes found in a cell's nucleus; passed on through generations of species if individuals survive and successfully reproduce
  • in line with Darwin's theory of evolution, it might also follow that genes form a basis of behaviour as both behaviour and genes appear to be heritable
• Genotype

  • particular set of genes that a person possesses, made up of DNA
  • genes only determine the potential for that characteristic
• Phenotype

  • describes combined effects of genetic makeup and surrounding environment on behaviour
  • observable characteristics of individual depend on the interaction of genetic and environmental factors
  • e.g - phenylketonuia is a genetic disorder that can lead to severe learning difficulties unless it's caught and the child is on strict diet e.g no eggs, meat, nuts etc
• Twin Studies

  • used to determine likelihood that certain traits have a genetic basis
  • done by comparison of concordance rates (extent to which both twins share same characteristic)
  • monozygotic (MZ) - one zygote - these twins are formed when a fertilised cell splits into 2 and forms 2 separate embryos
  • dizygotic (DZ) - formed when 2 separate eggs both become fertilised by different sperm cells
• Concordance Rates

  • MZ twins should have 100% concordance rate if particular characteristic is genetic - DZ will be lower and siblings will be 50%
  • comparisons can be made between twins raised together and twins living apart
• Research into the Influence of Genes

  • McGuffin (1996) - found if one MZ twin had depression there's a 46% chance the other twin will have it too - DZ twins was 20% chance
  • suggests there's a genetic component to illnesses like depression
  • if MZ twins have higher concordance rate than DZ then it shows there's a genetic element involved
• Adoption Studies

  • involve comparing a trait/characteristic between adopted children and their biological/adoptive parents
• MZ twins

  • have identical genotype but if one exercises more and lives in a sunnier climate their phenotypes will differ
• Evolution and Behaviour

  • evolution - changes in inherited characteristics in a biological population over successive generations
  • Darwin - process of natural selection; characteristics that aren't suited to a species environment will die out as it struggles to survive and with time will evolve over generations so that only adaptive characteristics remain in future offspring
  • Darwin emphasised 2 main concepts to the evolutionary theory - natural selection and sexual selection
• Natural Selection

  • animals with particular traits provide them with advantage and are more likely to survive and reproduce thereby passing on their 'adaptive traits' to offspring
  • behaviours need to adapt to environment animal is living in
  • happens naturally - selection occurs because some traits give possessor certain advantages. Therefore, possessor is more likely to survive and pass on these traits
• Sexual Selection

  • females are naturally more particular about who'll father their kid as she's limited in number of eggs she produces and has to carry and raise the baby
  • Buss 1994 - hetrosexual partner reference - men prefer younger women as they're more fertile - women prefer traits e.g having resources, ambition and success - we've evolved to have certain traits that make us attracted to the opposite sex
• Neurotransmitters

  • relates to chemicals in brain that regulate psychologial functioning
  • recognise role of chemicals in determining behaviour
  • imbalances in neurotransmitters are associated with abnormal behaviours
  • having low levels of serotonin is associated with developing depression/aggressive tendencies
  • having high levels of dopamine is linked to schizophrenia
  • activity in localised areas of brain is assocaiated with behaviour
  • brain scanning techniques/molecular imaging