Infradian rhythms

Question 1

What two things govern biological rhythms?

Answer 1

Exogenous zeitgeibers

Endogenous pacemakers

Question 2

What are exogenous zeitgeibers?

Answer 2

External changes in the environment

Question 3

What are endogenous pacemakers?

Answer 3

The body’s biological internal clock

Question 4

What is an infradian rhythm?

Answer 4

A rhythm that is longer than a day

Question 5

What is an example of an infradian rhythm?

Answer 5

Menstrual cycle

Question 6

What happens during the menstrual cycle?

Answer 6

During each cycle, there is a rising level of oestrogen which causes the development of an egg. Progesterone helps the womb lining grow thicker to facilitate the egg

Question 7

What are endogenous systems affected by?

Answer 7

Exogenous factors

Question 8

What is a woman’s menstrual cycle affected by?

Answer 8

Outside factors

Question 9

Outline Stern and McClintock’s study on menstrual cycles (1998)

Answer 9

• 29 women with a history of irregular periods
• Pheromones gathered from 9 individuals at different stages of the cycle on cotton pads from the armpit
• The cotton pads were worn for 8 hours to make sure the pheromones had been collected
• They were treated with alcohol and then frozen and rubbed on the upper lip of the other individuals
• On day one pads from the start of the cycle where applies to all 20 women and so on

Question 10

What were the results of Stern and McClintock’s study?

Answer 10

68% of women experienced changes to the cycle which brought them closer to the cycle of the donor
Outside influences do have an impact

Question 11

What is seasonal affective disorder?

Answer 11

Low mood and disinterest in everyday life, triggered by the winter months

Question 12

What type of infradian rhythm is SAD?

Answer 12

Circannual

Question 13

What do psychologists believe is implicated in SAD? Why?

Answer 13

Melatonin
During the winter, the lack of light in the light means that more melatonin is produced which has a knock on effect with serotonin - linked to onset of depressive symptoms

Question 14

What is there to be believed about the menstrual cycle?

Answer 14

It has an evolutionary basis
Back to caveman times when females would menstruate together to have babies at the same time so they could look after each others’ children

Question 15

What issues are there with the menstrual cycle studies into infradian rhythms?

Answer 15

It is a small sample
Only women so not generalisable to men
Women self reporting
There are a number of studies which don’t find synchrony

Question 16

What can also be used, other than women, to look at the role of pheromones?

Answer 16

Animal studies

Eg. Sea urchins

Question 17

What is a practical application of research into SAD?

Answer 17

Phototherapy which removes 60%

When a placebo was used 30% had reduced symptoms