Ultradian

• How long does an ultradian rhythm last?

  Less than 24 hours/one day
• What are the 5 sleep stages?

  • Stages 1 to 3: light sleep
  • Stage 4: deep sleep
  • Stage 5: REM sleep
• How long does a stage of the sleep cycle last?

  ~90 minutes
• Dream analysis experiments AO3:

  +supports psychology as a science

  +standardised procedure

  -subjective analysis

  -self report: social desirability effects, apprehension effects etc.