Research into Infradian Rhythms

Question 1

What is the menstrual cycle internally controlled by?

Answer 1

internally controlled by endogenous pacemakers such as hormones,
which are coordinated by the pituitary gland, to promote ovulation and stimulate the uterus
for fertilisation.

Question 2

What may the menstrual cycle also be influenced by?

Answer 2

external zeitgebers such as
pheromones, which are biochemical substances dispersed into in the air from the armpit.
These odourless chemicals are detected by other women through an organ in their nose which sends neural signals to the hypothalamus in the brain.

Question 3

What may the release of these pheromones therefore do?

Answer 3

coordinate menstrual cycles between different women.

Question 4

What did McClintock (1971) find?

Answer 4

-that females who spent extended periods of time together and did not
take oral contraceptives, tended to menstruate at the same time every
month
-the release of pheromones may have facilitated this synchronisation