infradian rhythms

• What is an infradian rhythm with an example


  Biological rhythms that take longer than a day to complete. e.g. menstrual cycle
• What is the role of exogenous cues in the menstrual cycle?


  • Menstrual cycle is an endogenous system but is influenced by exogenous factors (e.g. other women and their cycles)
  • Russell et al ('80) - said that when women live with each other for long times, they become synchronised
  • Penton-Voak et al ('99) - found that human mate choice varies. Women prefer 'slightly feminised' male faces when picking long-term relationship but during ovulation women prefer 'masculine' faces
• What was the McClintock (1998) study?


  • chose 29 students with a history of irregular periods
  • They took samples of 9 women at different stages of period by collecting the cotton wool pads that were kept under their armpits for 8 hours
  • These pads were frozen and then rubbed on the upper lip of the other pps
  • 68% synced to odour donor
• What is SAD?


  • Seasonal Affective Disorder
  • Persistent low mood
  • Symptoms are triggered due to lack of daylight
  • Melatonin can be a cause of SAD because the lack of light in winter means that the pineal gland secretes melatonin for longer so less serotonin is produced in the brain
• What was the evaluation for menstrual cycle research?


  • Evolutionary basis of menstrual cycle
  • Ancestors menstruated together to fall pregnant at the same time so that the newborns could be cared for collectively

  BUT

  • Validity has been questioned by Jeffrey Schank (2004)as they said there was competition for the highest quality male so they would avoid synchrony.
• What were the methodological limitations in synchronisation studies (McClintock)?


  • Extraneous variables and CVs - many factors change a cycle (e.g. stress, diet, exercise etc.
  • Results of the study was not higher than results that would occur by chance
  • Small sample sizes
  • Trevathen et al (1993) found no synchronisation