AO3

• Eval: Circadian Rhythms

  Pros:

  • Evidence - Siffre (1975)
  • Evidence - Aschoff & Weber
  • Ecological validity - shift scheduling that better align with natural rhythms, and use of artificial light to help regulate alertness for night shifts

  Cons:

  • Individual differences - some people are morning people, some people are night people, less generalisability
• Ultraradian/Infradian Pros:

  • Research support (I)- Reinburg (1967), exogeneous zeitgebers
  • Practical applications (U) - Led to sleep therapy development, improving health.

  Cons:

  • Individual differences (U)- REM sleep length varies due to social factors (work patterns), making it biologically reductionist.
  • Correlation, not causation (I) - Self-report data used in Seasonal Affective Disorder SAD studies limits causality
• Siffre: Biological Rhythm

  • Procedure: spent two months in an underground cave isolated from natural lights/clocks
  • Findings: found that the absence of light altered his circadian rhythm (SCN), as he thought the date to be a month earlier
• Aschoff & Weber: Biological Rhythm

  • Studied ppts living in a bunker with only artificial light
  • their sleep/wake cycle settled into longer hours of 25-27 hours highlighting the necessity of exogenous zeitgebers
• Reinburg(1967): Ultra/Infradian

  • examined a woman who spent 3 months in a cave with little light, her cycle shortened from 28 to 25.7 days supporting exogenous zeitgebers