Evaluation

• Shift work

  • Provides understanding of what happens when circadian rhythms are disrupted - desynchonisation
  • Night workers in shift work experience reduced concentration at around 6am (circadian troughs) - mistakes and accidents are more likely (Boivin et al)
  • Shift workers 3x more likely to develop heart disease (Knutsson)
  • Therefore, research into circadian rhythms has real-world economic value
• Counterpoint to shift work

  • Research into shift work uses correlational methods - difficult to establish whether desynchronisation is the cause of the negative effects - may be other factors
  • Solomon - high divorce rates may be due to sleep strain and other influences like missing family events
  • Therefore, may not be biological factors causing negative effects in shift workers
• Medical treatment

  • Circadian rhythms coordinate basic processes like digestion and heart rate
  • They rise and fall during the day, leading to chronotherapeutics - using biological rhythms to help administer medication
  • E.g. Aspirin is most effective taken last thing at night - prevents heart attacks (Bonten et al)
  • Therefore, circadian rhythms can help increase effectiveness of drug treatment
• Individual differences

  • Difficult to generalise
  • Aschoff and Wever, and Siffre's studies based on small samples
  • Sleep/wake cycles vary from person to person (Czeisler et al)
  • Vary from 13 to 65 hours
  • Duffy et al. - some people have a natural preference for going to bed and waking earlier ('larks') and vice versa ('owls')
  • Siffre - his own sleep/wake cycle had slowed over time
  • Therefore, it is difficult to use data for anything except averages, which may be meaningless