infradian rhythms

Question 1

what are infradian rhythms?

Answer 1

• takes longer than a day to complete.

- e.g the menstrual cycle.

Question 2

what did Stern and McClintock discover?

Answer 2

they discovered that exogenous zeitgebers may synchronise menstrual cycles.

Question 3

describe Stern and McClintock’s investigation.

Answer 3

• studied 29 women with irregular periods.
• pheromones were taken from women at different stages of their cycles, via a cotton pad under their armpits.
• these pads were cleared with alcohol and later rubbed on the upper lips of the other participants.
• 68% of women experienced changes in their cycle which brought them closer to the cycle of their odour donor.

Question 4

what is Seasonal Affective Disorder (SAD)?

Answer 4

• a depressive disorder with a seasonal pattern.
• symptoms are triggered during the winter months when daylight hours become less.
• caused by the longer secretion of the hormone melatonin because of the lack of light.
• has a knock-on effect on production of serotonin.

Question 5

one strength of research into SAD.

Answer 5

• its practical application.
• an effective treatment. for SAD is phototherapy, a lightbox that stimulates strong light in the morning and evening.
• relieves symptoms in up to 60% of sufferers.
• however, the same study recorded a placebo effect of 30%.
• this casts doubts on the real value of phototherapy.

Question 6

one limitation of exogenous zeitgebers synchronising menstrual cycles.

Answer 6

• the methodology used in synchronisation studies.
• many argue that many factors may change a woman’s menstrual cycle and act as confounding variables in research e.g stress, diet.
• any pattern of synchronisation is what we would expect to occur by chance.
• also research involves small sample and relies on Relf-reporting which may be inaccurate.
• this suggests that important aspects of these studies lack validity.