Ultradian rhythms

• How long does an Ultradian rhythm last?

  Less than 24 hours
• What is stage 1 of the sleep cycle?

  ‘Hypnogogic sleep’

  Alpha waves (high frequency, low amplitude)

  Beta waves (low frequency, low amplitude)
• What is stage 2 of the sleep cycle?

  Light sleep

  Brainwave patterns become slower and more rhythmic
• What is stage 3 + 4 of the sleep cycle?

  Deep sleep

  Stage 4 only occurs in first and second cycle

  Delta and theta waves (high amplitude and low frequency)

  Human growth hormone is released
• What is stage 5 of the sleep cycle?


  REM (dreaming)

  Body is paralysed to stop you acting our your dreams

  Alpha waves (high frequency, low amplitude)

  Beta waves (low frequency, low amplitude)
• What is some research into sleep cycles?

  Dement and Kleitman (1957) - used an EEG to monitor sleep patterns of adults

  Found REM activity was associated with dreaming as people who were woken up during REM recalled their dreams
• What are some strengths of the sleep cycle?

  • EEGs are objective, and proves we have a cycle every 90 minutes
  • Controls extraneous variables
  • Replications of studies show similar findings
• What are some issues with the sleep cycle?

  • Constant waking up causes a REM rebound - this affects sleep patterns so can’t generalise
  • P’s may be uncomfortable in the beds in the study so may have atypical sleep
  • P’s may usually co-sleep so sleep may be atypical
  • Tucker (2005) - Genetics may affect sleep patterns
  • Exogenous factors may affect sleep like temperature, light etc
  • Not all dreams happen in REM, some may happen in stage 4
• What is the basic rest activity cycle?

  During the day we move through periods of alertness and tiredness about every 90 minutes
• Who came up with BRAC?

  Kleitman
• What is an issue with BRAC?

  Evidence is anecdotal (not tested)
• What does Kleitman say proves we have a BRAC?

  10:30 am work breaks
• What is a study for BRAC?

  Ericsson - prodigious violinists tended to practice for 3 sessions a day for no more than 90 mins, with a break in between sessions to recharge
• What is an issue with Ericsson’s study for BRAC?

  They are atypical people as they are prodigious, so the study has low population validity