INFRADIAN

• WHAT IS AN INFRADIAN RHYTHM?

  rhythm that occurs less than once every 24 hours/ have a duration of over 24 hours

  -> longer gap between cycles
• EXAMPLE OF AN INFRADIAN RHYTHM?

  menstrual cycle (28 days)
• ENDOGENOUS PACEMAKERS INVOLVED IN MENSTRUAL CYCLE?

  • pituitary gland
  • oestrogen
  • progesterone
• EXOGENOUS ZEITGEBERS INVOLVED IN MENSTRUAL CYCLE?

  • food
  • stressors
  • other women who you spend time with
• RESEARCH ON INFRADIAN RHYTHM?

  Stern and McClintock
• STERN AND MCCLINTOCK'S RESEARCH?

  • 9 women with irregular periods wore sweat pads under armpits to collect pheromones
  • treated with alcohol and frozen
  • placed on lips of 20 more women with irregular periods
  • most women experienced changes in cycle, closer to whose sweat pad they were exposed to
• DISCCUSION OF STERN AND MCCLINKTOCK'S RESEARCH?

  Extraneous variables

  • many extraneous variables influencing cycle (stress/ diet/ exercise)
  • cannot say only women influenced cycle
  • alongside small sample size
  • possibility due to chance
  • decreases internal validity

  Biological approach

  • supports evolutionary theory
  • would benefit offspring's survival
  • women could support each other if they had children at the same time