Infradian and Ultradian Rhythms Flashcards
What are infradian rhythms?
Cycles that last longer than 24 hrs.
What are ultradian rhythms?
Cycles shorter than 24hrs, so can happen more than once in a day.
Give 3 examples of infradian rhythms.
Menstrual cycle.
Seasonal Affective Disorder.
Pregnancy.
Skin regeneration.
Migration patterns.
Breeding patterns.
What system governs the menstrual cycle?
The endocrine system.
State 3 hormones involved in the menstrual cycle.
FSH.
LSH.
Oestrogen.
Progesterone.
State 3 exogenous zeitgebers that can have an impact on the menstrual cycle.
Illness, (physical conditions of the body).
Stress and anxiety,
Medicines, (e.g. hormonal contraceptives).
Synchronising, (e.g. menstrual cycle aligns with those around you).
Outline Reinberg’s study from 1976.
Had a female PP spend 3 months in a cave with a small lamp as the only light source.
As a result of this her days (circadian rhythm) lengthened to 24.9 hours and her menstrual cycle (infradian rhythm) shortened to 25.7 days.
What did Reinberg’s cave study show?
This study shows that the levels of light in the cave could have affected the woman’s menstrual cycle.
After the study it took her body a year to readjust her menstrual cycle back to the original.
This research shows how infradian biological rhythms can be influenced by exogenous zeitgebers, such as light.
Give 3 evaluative points for Reinberg’s cave study from 1976.
Didn’t cover for confounding variables such as stress and exercise (weight changes). This weakens support for exogenous zeitgebers and the menstrual cycle.
There is only one participant, so findings cannot be generalised. Menstrual cycles are personal.
3 months is a very short time period for a menstrual cycle to change, this would only be 3 cycles - depending on what the norms for the participant is. This renders it more of a case study.
What is a pheremone?
A chemical substance produced and released into the environment by an animal, affecting the behaviour or physiology of others of its species.
What was found from McClintock and Stern’s study from 1998.
Found that when females received “odourless compounds” from the armpits of women in the latter half of their menstrual cycles, their cycle was shortened, presumably by the effects of the other women’s pheromones as they approached the end of their cycle.
However, if the compounds (including pheromones) were collected from women at the beginning of their cycle, this had the opposite effect, lengthening the cycle of those who had received the compound.
Outline the procedure of McClintock and Stern’s study from 1998.
The compounds were transferred by the women wiping a pad, which had previously been wiped across the donor’s armpit, above their upper lips.
What percentage of females experienced changes in their cycles, closer to that of their ‘odour donor’? What does this show?
(McClintock and Stern)
68%.
This shows that the menstrual cycle of a woman can be altered by communication via pheromones.
What happened if the donor’s pheromones were from women in the end of their menstrual cycle, when rubbed on the participants top lip?
(McClintock and Stern)
The participants cycle shortened.
What happened if the donor’s pheromones were from women at the start of their menstrual cycle, when rubbed on the participants top lip?
(McClintock and Stern)
The participants cycle lengthened.
What are 2 evaluative points that can be made about McClintock and Stern’s research?
McClintock and Stern – not all women experienced menstrual cycle changes.
McClintock and Stern’s sample were women with a history of irregular periods; meaning changes that were observed were no more likely to appear by chance due to the confounding variables.
Outline the 1993 research by Trevathan et al.
Failed to find synchronicity in the menstrual cycle in their female sample.
What is SAD?
A depressive disorder with a seasonal pattern and is diagnosed as a mental health condition in DSM-5.
What does SAD stand for?
Seasonal Affective Disorder.
What are the symptoms of SAD?
Persistent low mood and a general lack of activity and interest in life.
What type of rhythm is SAD?
A type of infradian rhythm called a circannual rhythm.
Why could SAD also be classified as a circadian rhythm?
However, it could also be classified as a circadian rhythm as the experience of SAD may be due to the disruption of the sleep/wake cycle, and this can be attributed to prolonged periods of daily darkness during winter.
