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