Biological

• According to the biological approach, humans are biological organisms made up of physiological processes
• The actions of genes, hormones, neurotransmitters and neurochemical mechanisms must be understood in order to explain behaviour fully
• Heritability coefficient


  It can be used to quantify the genetic or biological basis of a certain characteristic
• IQ is said to have a heritability coefficient of 0.5, and so the influence of nature (genetics) and nurture (the environment) are equal
• Behaviour genetics


  The study of the influence of an organism's genetic composition on its behaviour and the interaction of heredity and environment insofar as they affect behaviour
• Genotype


  An individual's genetic make-up, where a gene is a short section of DNA coding for specific proteins
• Phenotype


  The physical expression of an individual's genotype
• The interaction between the phenotype and the environment results in individual behaviour
• Epigenetics


  A change in gene expression, without altering an individual's genetic make-up. Epigenetic markers, such as DNA methylation and histone tail modification, can be left on DNA through exposure to certain environmental factors, such as specific diets and pollution
• Natural selection


  The mechanism of evolution. The theory suggests that any genetically-determined behaviour, which gives the individual a selective advantage (increasing their chances of surviving, reproducing and passing down this beneficial allele onto their offspring), will be present in future generations
• Genetically-determined behaviours with a selective advantage

  • Avoiding fire and deep water
  • Certain individuals having longer necks
  • Specific cows producing more milk
• Evolution


  The process by which organisms change over time as a result of changes in heritable physical or behavioural traits
• Practical application in the development of drugs

  • An increased understanding of the biological processes which underpin mental health diseases has led to the development of psychoactive drugs e.g. for depression and schizophrenia. These may target specific candidate genes to directly treat the disorder, or may alter neurotransmitter levels to help alleviate symptoms
• The biological approach suggests that all behaviour is caused by internal biological forces over which we have no control i.e. the influence of genes, hormones, neurochemistry etc.
• This has serious implications for the judicial system and the economy. The current judicial system expects individuals to take moral responsibility for their actions, and so such actions cannot be entirely blamed on genetic factors
• If, for example, a criminal gene or a schizophrenia gene was discovered, this could lead to 'diminished responsibility' of these individuals, as well as shorter prison sentences
• The economical impact would be that if such information about genes coding for mental health disorders or criminality were made public, then such individuals may be denied health insurance and jobs on this basis
• MZ twins usually show higher concordance rates for mental disorders and psychological characteristics compared to DZ twins
• This makes the naïve assumption that the only differences these twins have are genetic. MZ twins are more likely to grow up in the same household, be exposed to similar experiences and be raised using parenting styles
• This may explain the differences in concordance rates between MZ and DZ twins, as opposed to only genetic differences
• This may also explain why MZ twins often have higher concordance rates than ordinary siblings, despite both sharing 50% of genes
• This suggests that behaviour cannot and should not be explained in purely genetic terms (as suggested by the biological approach), without accounting for social contexts, through adopting an interactionist approach
• The biological approach


  • It uses EEG, PET and fMRI scans to objectively and systematically measure the biological or neural basis of behaviour. Drugs are also then developed on this basis, whilst family and adoption studies can lead to an increased understanding of the concordance rates and heritability of certain psychological characteristics. This increases the scientific credibility of Psychology, through the strict control of extraneous and confounding variables