Cards (2)

  • Implication - role of exogenous zeitgebers
    • Stern and McClintock - 29 women with irregular periods
    • Samples of pheromones gathered from 9 of the women at different stages via cotton pad on armpit for 8 hours
    • Pads frozen and rubbed on top lip of 20 women
    • 68% of women experienced changes in cycles closer to donor's
    • Therefore, infradian rhythms also use exogenous zeitgebers
  • Methodological issues
    • Many confounding variables in synchronisation studies
    • Any supposed pattern of synchronisation is no more than would have been expected to occur by chance
    • Explains why other studies (Trevathan et al.) failed to replicate findings
    • Therefore, studies are flawed, decreasing internal validity