Biological

• Assumptions of the biological approach

  • To fully understand human behaviour we must look at biological structures
  • An understanding of brain structures and function can explain behaviour
  • Chemical processes in the brain are responsible for psychological functioning 
  • Explain behaviour as the direct product of interaction within the body
  • Humans have biologically evolved but still share common features with animals
• Neurotransmitters

  Brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another
• Hormones

   Chemical substances that circulate in the bloodstream
• Different types of hormones

  Dopamine, Serotonin, Oxytocin, Norepinephrine, Epinephrine
• Dopamine


  excitable, pleasure, part of the reward system, motivating, recreational drugs release this hormone (cocaine)
• Serotonin


  mood regulator (used for anti-depressants), takes away extremes of ‘highs and lows’ (in ecstasy, MDMA→ can cause anxiety and depression in the long term)
• Oxytocin


  love’ chemical, sex, aggression
• Hormones behavioural effects

  • Serotonin: Low levels -> depression
  • Melatonin: High levels -> sleep
  • Adrenaline: High levels -> stress, emotion, arousal
  • Endorphins: High levels -> happiness, joy, sexual pleasure, exercise
  • Testosterone/oestrogen -> sex, aggression
• Heredity

  The passing of characteristics from one generation to the next through genes
• Genes

  Make up chromosomes, consists of DNA which codes for the physical features of an organism as well as psychological features
• Twin studies

  Studies that are used to experiment the likelihood that certain traits have a genetic basis by comparing the concordance rate (the extent to which both twins share the same characteristics)
• Concordance rate

  The extent to which twins share the same characteristic (expressed as a %)
• Monozygotic

  identical twins (100% genetic material, from one egg ‘mono’)
• Dizygotic

  Non-identical twins (50% genetic material, from two eggs ‘di’)
• Genotype

  The particular set of genes that a person possesses→ their actual genetic makeup
• Phenotype

  The characteristics of an individual determined by both genes and the environment→ how the genes are expressed through physical, behavioural and psychological characteristics. This illustrates an interaction between inherited factors (nature) and environmental factors (nurture)
• Evolution


  Human genes have evolved over millions of years to adapt behaviour to the environment. Therefore, most behaviour will have an adaptive/evolutionary purpose
• Charles Darwin


  (1859)

  Describes the process of natural selection; characteristics that are not suited to a species’ environment will die out as it struggles to survive and reproduce, and so over generations only those ‘useful’ adaptive characteristics will remain and continue to evolve and be inherited by future offspring
• Survival benefits


  • Examples might be aggressive behaviour or phobias
  • In line with Darwin’s theory of evolution, it also follows that genes form a basis of behaviour and psychological characteristics, as both behaviour/psychology appear to be heritable.
  • competing for resources or the compulsion to escape from threatening situations
• Evaluation: Strength

  Real world application

  • Provides clear predictions regarding the influence of biology on behaviour, while many other approaches do not 
  • Significant applications of biological research in the real world 
  • Example: research into neurochemical imbalance associated with depression has been used to create effective drug treatments such as antidepressants 
  • Wider implications: enabling a better quality of life in the community rather than hospitalisation
• Evaluation: Strength

  Scientific methods

  • Biological method uses a range of precise and highly objective methods 
  • These include scanning techniques such as fMRIs and EEGs
  • Advances in technology→ possible to accurately measure physiological and neural processes in ways that are not open for bias 
  • Based on objective and reliable data
• Evaluation: Limitation

  Biological determinism

  • Deterministic, sees human behaviour as governed by internal, genetic causes over which we have no control
  • BUT, we have seen the way in which an individual’s genotype is expressed is heavily influenced by the environment (phenotype) → not even identical twins who share the same genes are ‘identical people’
  • Are violent criminals excused for their actions by claiming they were controlled by a ‘crime gene’?
  • Biological view is too simplistic and ignores the effects of the environment (nurture)
• Natural selection

  • Critics such as Karl Popper claim that it is not possible to falsity the theory of natural selection as we cannot show evolution happening, only deduce it had taken place
  • Others claim that the basic principles are supported by fossil fuels