The McClintock Effect: Why the popular belief of periods syncing is just that, a belief.
We are so consumed by the idea of being someone’s ‘ride or die’ that we want everything to happen for both of us at the same time. You plan your daily chores together, indulge in endless gossip. We wear the same coloured clothes because twinning is the new ‘it’.
You go as far as planning your weddings on the same date because you are soul-sisters and sisters do everything together. But one thing you cannot do together is, menstrual synchrony; too technical to understand? Well, hold my water bottle.
Menstrual Synchrony or Period Syncing is a phenomenon or popular belief that came to light in a 1971 research paper published by Martha McClintock who claimed that when some girls spend a lot of time together, their periods tend to ‘sync up’.
This belief caught so much fire that some researchers took to research to find out whether this is true or just folklore to intrigue people.
Well, we have heard of the phrase ‘strangers turn family’, but has this belief taken it a bit too far? Let’s find out.
The McClintock effect:
Martha McClintock in 1971, conducted the research on 135 girls from Wellesley College, who lived in a girls’ hostel to check if their periods synced given the time they spent with each other. She found out that in fact, that was the case and their periods synced. This research was hence named as ‘The McClintock effect’.
You might think that I am talking in favour of the argument, but that’s not the case. Here are my observations about ‘The McClintock effect’. First off, she did not take into consideration the ovulation time of these girls. Ovulation time is important to be considered as this decides the menstrual cycle.
Secondly, when other researchers re-examined this research a few years later, they found that the girls had inflated their number of days. Hence, McClintock’s research had little merit to it.
However, this report can be credited for finding out that humans, and not just animals, released pheromones too. Pheromones are unconscious chemicals released that influence a creature’s behaviour and physiology. It is like a natural scent released by the body.
Similar Research on Animals and Humans:
Many researchers tried to get the same results as those of McClintock by conducting experiments on animals like Chimpanzees, rats, etc. However, they failed as their studies eventually found out that, due to natural causes, menstrual synchrony could not take place.
The father-son duo of Leonard and Aron Weller conducted this experiment on humans by studying the menstrual cycle of college roommates, sisters, mothers, athletes, etc. They found that sometimes the cycles matched, other times they didn’t. They concluded that there is no evidence to support that there is menstrual synchrony. And if it does exist, it can only happen by chance.
Facts about this Myth:
Let us see why this study fails to prove period syncing or Menstrual Synchrony:
1. Female Body Clock:
The body clock of every female is as unique as the fingerprint. You may try your hardest to sync up your period cycle with your best friend, but it won’t happen because your bodies are different.
2. Different Cycle Lengths:
The period cycle, i.e. the number of days between the first day of your first period and the first day of your next, also differs among women. For example, the period cycle of your roommate might be 30 days long and your cycle length may last up to 40 days. Hence, there is no question of your periods syncing with each other.
3. Genetic differences:
Even if there are twin sisters in a house, their genes are completely different. And hence the timing of their cycles may also differ.
4. Body Mass Index (B.M.I.):
The Body Mass Index is used to measure the body mass of an individual by taking their height and weight into account. It is used to determine whether a person’s body weight is in proportion to their height. Your roommate’s B.M.I. will differ from yours. Under no circumstance, can you make them match as you two are different individuals. Hence this is another important reason why your periods won’t sync.
5. Mental Health:
The mental health of two girls staying together may vastly differ, too. Take sisters for example. If one sister is facing mental health issues of any kind and the other one is not, then their cycles will differ as stress plays an important role in deciding your cycle.
6. Chronic Illness:
Chronic illnesses also have a deep impact on a person’s physiology. There are times when you may see your roommate suffering from a severe illness. So, no matter how close you two are, your roommate’s cycle will differ from yours.
7. Medications:
Medications also have a heavy impact on your body and can alter your cycles. You might be taking medications to control stress, while your roommate may be on birth control pills. Hence, this is another reason for your cycles to not sync up.
8. Natural Causes:
There are so many other natural yet unknown causes which could result in your cycles not matching up.
It is clear from above that your periods may sync and diverge due to the effect of time and the environment you grow in. If at all your periods do sync, they can only happen by chance.
So, while you two may feel like you have an eternal bond with each other and are ‘sisters-before-misters’ or ‘soul-sisters’, there are some things that are not in your control. Period! (Pun intended).
