biological approach

• human behaviour is due to an organic cause:

  • genetics - genotype and phenotype
  • brain structure
  • neurochemistry - neurotransmitters (serotonin, dopamine, GABA) and hormones (testosterone, adrenaline, oestrogen)
  • environmental factors
  • evolutionary approach (charles darwin)
• methodology for each

  • evolutionary approach - untestable, falsify
  • genetics - family studies ↓, twin studies ↓, adoption studies
  • neurochemistry - lab studies
  • brain structure - brain scans
• evolution and behaviour

  darwin argued, overtime organisms become adapted to their environment through biological evolution - refers to change that takes place in population's characteristics overtime. mechanism behind biological evolution is natural selection - process which inherited characteristics that enhance an individual's reproductive success or ('fitness') are passed on to next generation, and so become widespread in population overtime.
• buss (1989)

  studies 37 different cultures and found universal similarities in human mate preferences. women desired mates with resources (to provide for offspring) whilst men desired young physically attractive women (an indication of their fertility and reproductive value)
• the influence of genes on behaviour - genes: the mechanisms of heredity


  heredity is the passing of characteristics from one generation to the next through the genes, and is the reason why offspring 'take after' their parents in terms of psychological characteristic (such as intelligence or temperament), but how this characteristic develops depends partly of the interaction of the gene with other genes, and partly on the influence of the environment. the extent to which a psychological characteristic is determined by genes or environment is called the nature-nurture debate
• the influence of genes on behaviour: genotype and phenotype

  genotype - the genetic code that is 'written' in the DNA of an individual's cells

  phenotype - physical appearance that results from this inherited information

  not a direct relationship between the two. eg, someone may inherit a recessive gene for blue eyes, but won't be expressed if also have inherited a dominant gene for brown eyes from the other parent. meaning we cannot determine the genotype from only observing from the phenotype
• the influence of genes on behaviour: the genetic basis of behaviour

  each individual possesses a unique combo of genetic instructions, therefore we differ from each other in terms of personality, intelligence, abilities and so on. heritability refers to amount of variability in a trait within a population that can be that can be attributed to genetic differences between individuals between that population. the more a trait is influenced by genetic factors, greater the heritability. eg, studies of identical twins suggested that variation in individual intelligence could be 60-80% due to genes.
• brain structure

  4 lobes:

  • temporal lobe
  • frontal lobe
  • parietal lobe
  • occupatial lobe