Talk:Menstrual synchrony

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Related articles[edit]

Related articles from The Straight Dope:

And a study saying the effect doesn't exist:

--Apoc2400 07:44, 19 April 2007 (UTC)[reply]

Copyright[edit]

It appears that Lyrl copied and pasted text from straightdope, which is copyrighted. As such, it appears that the article is in violation of copyright (WP:COPYVIO).

The two sections below are copied word-for-word:

"Though a woman with a 27-day cycle might initially have her onset on the same day as a woman with a 29-day cycle, the next month she'd be two days earlier, the month after that four days, and so on."
"Assuming an average cycle of 28 days, the maximum time between two women's onsets is 14 days. Since the minimum is zero, the average difference"

Nephron  T|C 04:30, 23 June 2007 (UTC)[reply]

I've paraphrased the sentences that Nephron was concerned about. I appreciate other's attention to these details, but I believe the copyright tag is meant for images, or for entire articles that are copy-and-pasted, not two sentences out of a several paragraph article. Lyrl Talk C 00:42, 24 June 2007 (UTC)[reply]

Kohl study[edit]

A reference to a study authored by James V. Kohl was recently added. I reverted the additions supported by the ref (see my edit summary for reasons), but thought others might benefit from a link to the article: Human Pheromones: "Integrating Neuroendocrinology and Ethology" LyrlTalk C 17:53, 30 November 2008 (UTC)[reply]

Criticism is meandering and poorly referenced[edit]

The criticism section is poorly constructed. It waffles on where a simple sentence relating methodological weaknesses in existing studies would suffice. Using a poorly written website that doesn't even cite the appropriate studies is not impressive either. The bulk of the Straight Dope article actually comes from a paper from Schank- http://www.ncbi.nlm.nih.gov/pubmed/11334217 so that should be explicit. Whoever put in the SD reference might want to go and read the reply to the Schank paper, by the way. Ninahexan (talk) 04:50, 6 September 2010 (UTC)[reply]

References are poor[edit]

We're relying on the New York Times as a source? They cover mostly politics! How about at least Scientific American? [1] --Uncle Ed (talk) 04:23, 7 June 2011 (UTC)[reply]

Neutrality vs. pseudoscience[edit]

I don't want to elevate pseudoscience to an "endorsed view", so that people coming to Wikipedia think our Scientific Point Of View has endorsed menstrual synchrony, unless that is really what the science says. On the other hand, I don't want to accuse anyone falsely of pseudoscience.

So tell me what category to place this phenomenon:

  1. Proven science, with some "skeptical hold outs" (like Anthopogenic Global Warming Theory is treated)
  2. Controversial
  3. Disproven, with only the original "discoverer" and a few others on the "fringe" making a claim

Any comments? --Uncle Ed (talk) 11:14, 7 June 2011 (UTC)[reply]

  • We don't need to add a category as this is still unproven but not firmly in the pseudoscience category either. Nice work on the article. --John (talk) 15:37, 7 June 2011 (UTC)[reply]
Thanks. --Uncle Ed (talk) 15:53, 7 June 2011 (UTC)[reply]
I'm a bit frustrated. I know when you do an asbestos study or a cancer and smoking study, you have to ask people what they did years ago. But with a cohort of women - like recruits in a barracks, or students in a dorm - couldn't you just ask each lady to keep private records, and then show them to the researcher at an opportune time?
It reminds me of how people used to say that kids who eat "too much sugar" get hyperactive, and then it turned out no one had even bothered to do a study that compared (1) actual sugar intake and (2) observed restlessness. It didn't take long to establish that there was no correlation! --Uncle Ed (talk) 05:28, 4 January 2012 (UTC)[reply]
I wouldn't say that it is pseudoscience, but the current scientific evidence pretty conclusively demonstrate that it does not exist. Overtime, I plan to gradually update this article.--I am One of Many (talk) 05:15, 16 June 2013 (UTC)[reply]

June 2013[edit]

I will be updating this article this summer. I plan to summarize all major studies as well as issues raised by various researchers. The goal is a comprehensive article on menstrual synchrony and related phenomena in the few other species for which it has been reported.--I am One of Many (talk) 19:51, 18 June 2013 (UTC)[reply]

In doing so, I hope to address the issues of references etc. that have been raised regarding this article.--I am One of Many (talk) 19:53, 18 June 2013 (UTC)[reply]

July 2013[edit]

Chris, I'm sorry if I stepped on your edits. There was an edit conflict while I was working on my latest edit, which took around 10 minutes.

Feel free to revert again, if you need to, to restore your additions. If so, I'll redo my work later. --Uncle Ed (talk) 19:02, 20 July 2013 (UTC)[reply]

Would you guys like to discuss the structure of this article here? My plans were to turn this into a good article over the next couple of months as I have time to work on it. I think what is especially interesting is that it is a phenomenon that does not exist, yet many of most people this it does exist and there is an explanation for why they do think it exists.--I am One of Many (talk) 20:56, 20 July 2013 (UTC)[reply]
I'd like to frame it as a phenomenon that some researchers claim exists (like cold fusion) while others report being unable to reproduce those results. I'd like to expand on statistical critiques.
More importantly, I'd like to state it in a form that can be tested. Consider that there is a theory that carbon dioxide drives air temperature. Calling the CO2-temp link a "known" or "purported" phenomenon misses the point: there is a theory that changes in the first cause changes in the second. This can be checked by examining the historical temperature record, and this requires some simple or medium-level statistics. Likewise, with the cycle synch theory. It can be tested by conducting experiments, such as the year-long study of 186 ladies in China. --Uncle Ed (talk) 22:36, 20 July 2013 (UTC)[reply]
I think we are in broad agreement. I'll summarize the Chinese study, probably this weekend. I'm also planning to elaborate the statistical problems. Now, if you really want to see some cold fusion check out pheromones regarding humans. That is a future project. Take a look at The Great Pheromone Myth (also a great source for here).I am One of Many (talk) 00:01, 21 July 2013 (UTC)[reply]
I like what you added about the Chinese study. I'm interested in the statistics. Has anyone compared the cycles of ladies residing together with unrelated ladies's cycles? You know, some kind of control group. --Uncle Ed (talk) 01:20, 21 July 2013 (UTC)[reply]
Since the typical hypotheses proposed to explain synchrony are close proximity (e.g., meditated by pheromones) or friends ship (cause by whatever mechanism has never been specified), the typical control is to randomly pair or group women in a study that don't meet the first two criteria. This is not altogether satisfactory since women who come from the same dorm or even college still may share some degree of spatial proximity. So, ideal experimental controls are problematic, however, since the expected degree of synchrony can be computed (or approximated), it is possible to calculate whether cycle onsets are closer together than expected by chance.I am One of Many (talk) 06:15, 22 July 2013 (UTC)[reply]
One of the things that make menstrual synchrony an interesting topic is that is (was) so widely accepted in biology and psychology as a real phenomenon. I think one thing I will do in the next couple of weeks is check various college textbooks that cite the phenomenon and newer ones to see if recent research has begun to enter textbooks. It might turn out to be an interesting section, but first we will have to find out what is there.I am One of Many (talk) 06:15, 22 July 2013 (UTC)[reply]

Chris, thanks for mentioning the statistics of coinciding cycles. It adds an important dimension to the article. --Uncle Ed (talk) 18:22, 21 July 2013 (UTC)[reply]

Menstrual synchrony as theory[edit]

Ed, strictly speaking menstrual synchrony is not a theory or hypothesis. It is a theory or hypothesis that it exists. There is little doubt that it is a false theory, but given the title of the article, we have to refer to it as a phenomenon. I think to best express the current scientific thinking, it has to be a little skeptically stated. So, I would propose the first sentence should read:

Menstrual synchrony is a purported phenomenon in which menstrual cycle onsets (i.e., the onset of menstruation or menses) become closer together in time than they were at an earlier time.

I am One of Many (talk) 20:53, 20 July 2013 (UTC)[reply]

Why not treat it with the same dignified, standoffish, neutral attitude we give cold fusion and homeopathy? The phenomenon would be that women's cycles are (reportedly) found in synch (somewhat). The theory would be that it is a frequent, even typical occurence.
I neither wish to make it seem more "true" by calling it a theory, nor to make it seem more "false" by calling it a purported phenomenon. Some lady scientist got a paper through peer review (while barely out of college, or still in it); but it's not for me as a writer to say she was correct or incorrect. We have a section on attempts to reproduce her results which is pretty clear. --Uncle Ed (talk) 22:23, 20 July 2013 (UTC)[reply]

Proposed move[edit]

I'm thinking of moving the article from Menstrual synchrony to Menstrual synchrony theory. The article is about the hypothesis that women's menstrual cycles will synchronize in certain situations. The article devotes considerable attention to whether the phenomenon has ever actually been observed - or whether the statistics used to support the hypothesis were improperly calculated. In other words, does it really happen, or does it just appear to? (We remember coincidences but forget the "lack of coincidence".)

Without prejudice to the truth or falsity of the theory, I think it would help our readers if we moved it as proposed above. --Uncle Ed (talk) 15:12, 22 November 2013 (UTC)[reply]

Ed, There is no source to justify this move. Nobody refers to this phenomenon as "menstrual synchrony theory". There is a purported phenomenon and there are a number of theories proposed to explain it, but it should not be called menstrual synchrony theory.I am One of Many (talk) 16:14, 22 November 2013 (UTC)[reply]
  • I concur with User:I am One of Many Regardless of its verifiability as a theory (Most of Wikipedia is unsubstantiated and many scientific articles are not available to Wikipedia editors or the readership to provide a legitimate base to its authenticity), it is proposed as a argument of scientific phenomena. However, I believe it ought to be left as it is, with the article opening summary simply providing a clear explanation of its controversiality. Stevenmitchell (talk) 23:11, 18 March 2014 (UTC)[reply]

Methodical[edit]

Could someone else explain to IP 94.216.86.84 that they do not have a proper understanding of English and don't understand the meanings of "methodical" and "methodological". --I am One of Many (talk) 22:52, 2 February 2014 (UTC)[reply]

"Methodological" is correct in both cases. "Methodical" characterises an approach, ie a scientist may work in a methodical manner. "Methodological" means, roughly, "concerning methods". Adrian J. Hunter(talk•contribs) 04:46, 3 February 2014 (UTC)[reply]

Terminology[edit]

We still need to distinguish between a number of things:

  1. times when a number of women's periods have the same onset
  2. the (theorized) process by which those onsets to come into (near) synchrony
  3. the scientific dispute over whether the phenomenon really occurs

I suppose this clarification will improve the article and even result in renaming it. --Uncle Ed (talk) 15:01, 2 October 2016 (UTC)[reply]

How to describe the research[edit]

I'm getting different ideas about how the "research" was conducted. How did Ms. McClintock conduct her study? Was it double-blind? Did anyone keep records?

  • McClintock observed 135 female Wellesley College students living in the same dorm and found “a significant increase in synchronization of onset dates” among the women who spent a lot of time together.

Did she personally observe these women? Did the women themselves keep careful records, month after month for years at a time? Or did McClintock ask them to recall their period onsets - relying on human memory more than on written records?

There's also the question of how much of an overlap should be regarded as "synchrony":


  • This idea that this does not exist asks us to trust scientific studies (which are few and flawed) over what women over time and geography have experienced. Therefore a greater weight should be given to women's stories of the phenomenon.
  • This article wants to blame the moon as if it couldn't be both women's hormones and the moon working together to help women reset to the natural rhythms of nature. A worldwide worldview would reveal that in historical times it was known that women living close together would synchonize. As such this article only looks at the western view.
  • The studies ought to also look at how closely women lived together. Were they just classmates, or did they live in the same rooms, sleep in the same rooms and use the same bathrooms? — Preceding unsigned comment added by 2601:14B:4401:D5C0:5CA0:DCB6:D24:A4BC (talk) 02:18, 18 October 2016 (UTC)[reply]

Then there's the question of whether it every really happens at all:

  • While some of the researchers who followed McClintock were able to replicate her findings, many didn’t find evidence of menstrual synchrony. In 1992, researcher H. Clyde Wilson found errors in McClintock’s study model, specifically her sample selection and method of determining period start dates at the beginning of her study. When he corrected for those errors, he found no significant evidence of menstrual synchrony. The Huffington Post
    • Comment Yes, all of the questions you raised are issues. It is interesting in that a number of studies reported synchrony due to a misunderstand of what synchrony is, how to measure it, and statistically test it. I am planning to work on the history when I have time.--I am One of Many (talk) 04:54, 3 October 2016 (UTC)[reply]

"alleged" an unsuitable adjective for lead-in[edit]

Should we consider "alleged" a weasel word here? It certainly detracts from the clarity of the article. — Preceding unsigned comment added by 2001:56A:7042:6000:F585:54DF:2183:B0C8 (talk) 22:46, 23 August 2017 (UTC)[reply]

As the article makes clear, the reality of menstrual synchrony is greatly disputed, many considering it to be a complete myth. That needs to be indicated to the reader as soon as possible, and "alleged" does the job. If you want to suggest an alternative form of wording, fine, but I fail to see how "alleged" can be seen as a weasel word, and I fail to see how it "detracts from the clarity of the article" – to my mind, it adds to the clarity. Eric Pode lives (talk) 21:47, 24 August 2017 (UTC)[reply]
I agree with Eric Pode lives. EMsmile (talk) 14:53, 8 August 2018 (UTC)[reply]

Some tidying up together with culture and menstruation[edit]

I've done some tidying up to reduce overlap and repetition with culture and menstruation. Both articles had used the same paragraphs, quotes and images. I have tried to sort that out better now so that they don't overlap so much (in the section on myths). EMsmile (talk) 14:53, 8 August 2018 (UTC)[reply]

Almost all of the culture stuff does not belong in the article.--I am One of Many (talk) 04:26, 9 August 2018 (UTC)[reply]
Which sections do you mean exactly? Tell me the headings? I am happy to move it. EMsmile (talk) 05:22, 9 August 2018 (UTC)[reply]

Hypotheses Explanation?[edit]

Perhaps it is because I am not a biologist, but I fail to see a clear connection or causal relationship between the investigated hypotheses and estrous synchrony. The text reads: "They tested three hypotheses about the adaptiveness of estrous asynchrony: (1) females become asynchronous to increase copulation frequency and opportunities for giving birth; (2) paternity confusion to reduce infanticide; and (3) sperm competition." I don't get how asynchrony would increase copulation frequency. Can't they copulate whenever and however frequently they feel like? And how does asynchrony increase opportunities for giving birth? I'm probably missing something, but I would think asynchrony would only shift the birth timing, not increase the frequency. (Think of a sine wave undergoing translation; a phase shift would not alter the frequency or period).

Furthermore, I don't see any connection to paternity confusion, infanticide, or sperm competition. I am not even completely sure why paternity confusion would lead to infanticide. Or is it saying paternity confusion reduces infanticide? As in, the male does not know who the father is, so would not commit infanticide due to the possibility it is his? Or is the male confused into thinking the offspring is not his and so mistakenly commits infanticide?

I'll admit I can be slow to piece things together at times, but I honestly feel this article expects too much of the reader. More detailed explanations would be helpful. 66.91.36.8 (talk) 05:12, 3 April 2022 (UTC)[reply]

String Figure[edit]

I fail to see how the string figure represents menstrual synchronization. It would make sense to me if one hand had three separate strands and they intertwined into one on the other hand (three distinct cycles merging into one), but the picture shows three separate strands on both hands as if nothing changed. There is some interlacing/tangling midway, but the strands still separate at the other end and thus symbolically appear to remain distinct cycles. Was the picture a mistake or am I missing something? Is it a case of "lost in translation"? 66.91.36.8 (talk) 06:43, 3 April 2022 (UTC)[reply]

Big question
I think we're all missing something regarding the string figure. I find that the conflation of different sciences confuse the percept, or what it is that is studied. First of all it needs to be clarified to what extent we're studying a complex of anthropological phenomena. Then we need to figure out how to methodologically investigate the proposed diverse phenomena's biological, i.e. pheromonological and evolutionary aspects..
It is unclear whether the Yolŋu peoples string figure is explaining something directly, or if it is merely put there in order to state that menstruation and fertility-cycles are intrinsic parts of myth, rite and cosmology of the Yolŋu peoples, and a further common theme in anthropology and (pre)history of religion. There's a couple of things that this image of the string figure maybe hints at which seems to be an overlooked part of the complex that this article and the science needs to clarify further:
a) The purported phenomenon is to be regarded as an interlocked, combined and idealized synchrony and asynchrony of menstruation in relationship to culturally conditioned communal behaviour regarding sex, breeding and pleasure-economy.
b) The purported phenomen is variously ritualized and mythologized/cosmologogized, necessarily part of a bigger picture studied by social and cultural anthropology of kinship, ritual behaviour, fertility and varied gender relations of moieties, exogamic and endogamic.
c) Is the phenomenon studied merely idealized, or does cyclic ritual behaviour as proposed by cultures/groups that idealize the phenomenon have an effect advocating a biology of synchrony?
d) If the phenomenon is a virtue to some extent, as proposed by T. Buckley (1988): "Menstruation and the power of Yurok women (cf. ref. 38), how to study it in a methodological manner?
It appears to be evidenced beyond doubt that asynchrony is a fact, yet we cannot conclude that asynchrony is the evolutionary fittest, or "most natural". It yet cannot be excluded that a subtle basis for an evolutionary preferred synchrony (i.e. menstruation as virtue combined with pheromonic cause and effects) has been obstructed for ideological, political, or religious reasons, in order to subdue feminine power over procreation, off-spring, sex and the economy of pleasure.
The management and process of method-creation and experimentation in order to encompass this tremendous lacuna of scientific research needs to be extra-ordinarily aware of every element and aspect obscuring our scientific interpretation of nature, beginning with the four idols of Francis Bacon and be on par with contemporary research on the power and effect of bias. Xactnorge (talk) 16:17, 22 February 2024 (UTC)[reply]

Requested move 21 July 2023[edit]

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: not moved. (closed by non-admin page mover) – MaterialWorks 11:06, 5 August 2023 (UTC)[reply]

Menstrual synchrony → Menstrual synchrony hypothesis – To better reflect the current status of topic; also with consistency with naming in Category:Biological hypotheses. fgnievinski (talk) 16:38, 21 July 2023 (UTC) — Relisting. ❯❯❯ Raydann(Talk) 10:57, 29 July 2023 (UTC)[reply]

  • Doesn't seem to be necessary; many of the Category:Biological hypotheses do not have the word "hypothesis" in the title, and a number of those that have it use it to avoid ambiguity with another term. —  AjaxSmack  04:18, 26 July 2023 (UTC)[reply]
Note: WikiProject Women's Health has been notified of this discussion. ❯❯❯ Raydann(Talk) 10:57, 29 July 2023 (UTC)[reply]
Note: WikiProject Medicine has been notified of this discussion. ❯❯❯ Raydann(Talk) 10:57, 29 July 2023 (UTC)[reply]
  • Followed notification at WT:WH (Weak) oppose not seeing enough consistency at the indicated cat for me to ignore an argument for title concision. Little pob (talk) 11:34, 29 July 2023 (UTC)[reply]
  • Oppose per WP:CONSISTENT and WP:CONCISE. Just seems unnecessary. Rreagan007 (talk) 18:28, 29 July 2023 (UTC)[reply]
  • I saw the note at WT:MED. I don't care. Either title is fine. WhatamIdoing (talk) 19:29, 29 July 2023 (UTC)[reply]
  • Oppose Menstrual synchrony is a putative phenomenon and not a hypothesis, and this is how it is understood in the scientific literature. For example, evolution is a phenomenon and natural selection is a hypothesis about how it occurs. I am One of Many (talk) 21:01, 30 July 2023 (UTC)[reply]
  • Oppose. The lead very clearly says that this is a contested idea, so I don't think the word "hypothesis" in the title would add anything (WP:CONCISE). Sorry. Dr. Vogel (talk) 12:45, 1 August 2023 (UTC)[reply]
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

First sentence writing is unnecessarily complicated[edit]

I, a layman, had a hard time understanding what the process described is by reading this sentence: "Menstrual synchrony, also called the McClintock effect, or the Wellesley effect, is a contested process whereby women who begin living together in close proximity would experience their menstrual cycle onsets (the onset of menstruation or menses) becoming more synchronized together in time than when previously living apart."

Wouldn't it be better to just say "Menstrual synchrony, also called the McClintock effect, or the Wellesley effect, is a contested process whereby women who begin living together would experience their menstrual cycle onsets becoming closer in time"?

I feel there's a lot of unnecessary repetition as it is. Ninito159 (talk) 11:53, 11 August 2023 (UTC)[reply]

Missing male effects[edit]

In my opinion, that article is misleading. It lacks male effects in research on women. The root cause is the presence of men, which will lead to synchronization in women. It would be important to examine this on a community basis, not in purely female groups. This is an evolutionary pattern, not a female interaction.

source: Male Axillary Extracts Contain Pheromones that Affect Pulsatile Secretion of Luteinizing Hormone and Mood in Women Recipients https://academic.oup.com/biolreprod/article/68/6/2107/2683595

Pheromones: The Scent of a Male https://www.sciencedirect.com/science/article/pii/S0960982214001870

The statement of the article that "Reviews in 2006 and 2013 concluded that menstrual synchrony likely does not exist." is not valid. HummelZsolt (talk) 08:25, 2 October 2023 (UTC)[reply]

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