Infradian rhythms+ the menstrual cycle

Question 1

Outline infradian rhythms (8marker)

Answer 1

-Infradian rhythms are biological rhythms that last longer than 24 hours, for example the menstrual cycle (24 hours)
-The menstrual cycle is endogenously controlled by biological factors like hormones; the hormones involved are oestrogen, which stimulates the release of the egg during ovulation, and progesterone, which maintains the uterus lining in case of pregnancy
-Research also demonstrates that external cues can also influence infradian rhythms like the menstrual cycle
-McClintock (1971) studied the period duration of women who lived in the same dormitory in university
-It was found that menstrual synchronisaiton occurred between women in the same friendship group as a result of pheromones
-This provides support for the idea that infradian rhythms can be influenced by exogenous zeitgebers (external cues) such as pheromones
-HOWEVER
-The validity of menstrual synchronisation has been criticised, as McClintock (1971) failed to control for confounding variables such as diet and stress, which may have affected the length of the menstrual cycles
-This makes it difficult for the researchers to confidently establish a cause and effect relationship between pheromones and the menstrual synchronisation, reducing the validity of results