convergent cycles (FAQ?)
Carla Schack
section of the FAQ was not posted here, and when I tried to look it up on
the web, it wouldn't connect (possibly due to a screwy connection from my
end) so I tried to FAQ it and now I'm asking.
mostly a question for females or doctors, but does anyone have supporting
evidence, annecdotal or otherwise for the idea that a large group of
females will tend to have their monthly cycles line up and get into
synch? I've heard the "yeah, I went to this all girls summer camp where two
weeks after we got there everyone would start at once and we'd all be regular
together for the rest of the time there." but only from a couple of
people and never anything scientific.
I realise there aren't a great number of females on the net, but I
thought I'd try anyway, since I was curious about this.
--
The Big Kahuna Burger,
csc...@emerald.tufts.edu
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Ian A. York
Carla Schack <csc...@emerald.tufts.edu> wrote:
>
>females will tend to have their monthly cycles line up and get into
>synch? I've heard the "yeah, I went to this all girls summer camp where two
Even though I'm not female and never went to summer camp, and this
information isn't anecdotal, I certainly hope you'll accept it from me
anyway.
The answer is: Yes.
Weller L. Weller A. Avinir O.
Menstrual synchrony: only in roommates who are close friends?.
Physiology & Behavior. 58(5):883-9, 1995
" Menstrual synchrony was found among roommates who were close friends.
Synchrony was not found for roommates who were not close friends, nor by
housing units. The phenomenon of menstrual synchrony may more likely
occur among close friends and women with intensive social contact than
under the conditions common to university dormitories."
You can also readily find a review of the subject:
Weller L. Weller A.
Human menstrual synchrony: a critical assessment.
Neuroscience & Biobehavioral Reviews. 17(4):427-39, 1993
Ian "periodic" York
--
Ian York (iay...@panix.com) <http://www.panix.com/~iayork/>
"-but as he was a York, I am rather inclined to suppose him a
very respectable Man." -Jane Austen, The History of England
ann logue
>large group of
>females will tend to have their monthly cycles line up and get into
>synch? I've heard the "yeah, I went to this all girls summer camp where two
>weeks after we got there everyone would start at once and we'd all be regular
>together for the rest of the time there." but only from a couple of
>people and never anything scientific.
Let's see, this is all from recollection, but the University of Chicago
Alumni Magazine had an article a while back on a faculty member
who researched this very thing for her _undergraduate_ thesis and
who proved it and who got published in _Nature_ (or maybe _Science_)
which is virtually unheard of for any thesis, let alone by an
undergraduate. This would have been sometime in the 1970's.
How's that for anecdotal fact? A trip to the library may fill in
those gaps, or try calling the University of Chicago directly to
see about the back issue (sometime in the last year or two. It's a
great magazine as alumni publications go, but not so great that it
is spared the recycling bin after it is read.)
Annie
Hal Sadofsky
>synch?
Yes, lots of people have scientific (or at least what passes for that)
evidence both for and against this happening. It is amusing to do a
medline search under the keywords menstrual synchrony, and read the
varied accounts in the abstracts you find.
It looks like the jury is still out, but there are plenty of studies just
in the last few years (and this has been looked at for a long time) that
support both points of view.
Hal Sadofsky
JoAnne Schmitz
>Carla Schack (csc...@emerald.tufts.edu) wrote:
>: mostly a question for females or doctors, but does anyone have supporting
>: evidence, annecdotal or otherwise for the idea that a large group of
>: females will tend to have their monthly cycles line up and get into
>: synch? I've heard the "yeah, I went to this all girls summer camp where two
>: weeks after we got there everyone would start at once and we'd all be regular
>: together for the rest of the time there." but only from a couple of
>: people and never anything scientific.
From _The Wise Wound_ by Penelope Shuttle and Peter Redgrove, Bantam
Books, 1990, ISBN 0-553-34906-6:
"Martha McClintock has shown, in an important article in _Nature_
[McClintock, Martha K. 1971. Menstrual synchrony and suppression.
_Nature_, vol. 229, 22 Jan. 1971, pp. 244-245], that women living
together can beat out a strong co-operative menstrual
rhythm....McClintock worked with 135 women, and allowing for other
possibilities, such as a similar life pattern, repeated stress
periods, and seasonal variations in commonl eaten foods, found
undoubted menstrual synchrony that took about four months to establish
itself among people who spent time together."
>So far I haven't seen this in 4 out of 5 FAQ parts. I would also like to
>know. I've heard it said that there is a "dominant" female, and everyone's
>cycles get tuned to hers. Something to do with chemicals, like that
>pheromone/sexual attraction thing.
"McClintock suggest that one of the mechanisms could be pheromonal."
I recall reading about a study where women were induced to synchronize
with women they never met or saw by having the sweat of the other
woman swabbed under the test subject's nose every day.
>I have 5 sisters, and we joke about this
>often. We haven't lived together since our teens, and I recall being in sync
>back then, but not as the norm. I remember other times at work when the
>mostly female staff was in sync, and we all knew it. The commiseration and
>possible friction made it memorable, perhaps exagerrating such occurrences
>into legend. Offhand, I can't think of a plausible evolutionary or biological
>reason for such a phenomenon.
There might be a two-step explanation. First, during menstruation sex
may be taboo and/or less desired by the woman. Second, if everyone is
menstruating at the same time, no one is going to screw around with
your husband while you're "not available" since they aren't available
either. Weak, I know.
On the other hand, there may be no "reason" for it, it might just
happen as a by-product of our metabolisms and hormones. Not
everything has a reason to exist.
JoAnne "synchronicity" Schmitz
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-----------------------------------------------------------
Craig Myers
>>large group of females will tend to have their monthly cycles line up and get into
>>synch?
>Let's see, this is all from recollection, but the University of Chicago
>Alumni Magazine had an article a while back on a faculty member
>who researched this very thing for her _undergraduate_ thesis and
>who proved it and who got published in _Nature_ (or maybe _Science_)
>which is virtually unheard of for any thesis, let alone by an
>undergraduate. This would have been sometime in the 1970's.
Using various keywords and the Medline search engine back to 1966, I
found a few papers of interest.
The first is this one, which is a rebuttal of sorts to a previous
paper published in 1971 by a woman named McClintock; could this be
the woman to whom you are referring? [without knowing her first
initial, I couldn't find the paper[s] in question. Anyone else?]
>>>>>
Unique Identifier
2080600
Authors
Kiefhaber SH. Gravel V.
Title
Two sudies of menstrual synchrony: negative result.
Source
Psychoneuroendoriology. 16(4):353-9, 1991.
Abstract
In 1971 McClintock reported menstrual synchrony in pairs and groups
of women who spent time together.The two studies reported herein,based
on the methods and research design introduced by McClintck, fail to
replicate her results.The first study is of a sample of 132 women who
were sorority members or roommates of sorority members living on the
campus of a large coeducational state university. The second study is
of a sample of 24 women who were members of a cooperative house near
the same university. In the subjects fromboth studies, the final mean
onset absolute difference is greater than the initial mean onset
absolute difference, and there are more nonsynchronous pairs of
subjects than synchronous pairs. The sample from the sorority study
was progressively reduced to exclude those subjects with irregular
menstrual cycle lengths and those pairs in which one subject was
taking oral contracepives. Menstrual synchrony did not emerge in the
reduceded sample. Thus, whether or not menstrual synchrony occurs
among women who spend time together should still be considred a
hypothesis requiring further investigation.
>>>>>>
The next regards a case for whom you would surely expect menstrual
synchrony; lesbian couples. These authors found no such instance:
Unique Identifier
94022774
Authors
Trevathan WR. Burleson MH. Gregory WL.
Institution
Department of Sociology and Anthropology, New Mexico State
University, Las Cruces 88003.
Title
No evidence for menstrual synchrony in lesbian couples.
Source
Psychoneuroendocrinology. 18(5-6):425-35, 1993.
Abstract
Menstrual synchrony was investigated in a sample of 29 cohabiting
lesbian couples, ranging in age from 22 to 48 years. One or both
partners kept prospective daily records of variables including menses
onset dates, intimate contact, and sexual activity. All women reported
daily intimate interaction with their partners; none reported intimate
interaction with men. Despite these potentially optimal conditions for
the manifestation of synchrony, the differences between dyad members
in menses onset dates were distributed randomly, and there was no
evidence of convergence. In fact, most dyads exhibited divergence of
onset dates.
> Interruption by Craig:
[N.B. this sentence at the end of the abstract]
Reasons for lack of synchrony in this sample are discussed; one
conclusion is that there is no solid evidence that menstrual synchrony
is a stable attribute of past or contemporary human populations.
>>>>>>
Weller and Weller, however, found ample evidence of synchrony in the
following two papers:
Unique Identifier
93066834
Authors
Weller A. Weller L.
Institution
Department of Psychology, Bar-Ilan University, Ramat Gan, Israel.
Title
Menstrual synchrony in female couples.
Source
Psychoneuroendocrinology. 17(2-3):171-7, 1992 May-Jul.
Abstract
The menstrual cycles of cohabitating women have been found to
synchronize, possibly through social and pheromonal mechanisms. The
extent of this phenomenon, menstrual synchrony, was examined in 20
couples of lesbian women. Synchrony was very frequent, with half the
subjects menstruating within 2 days of their partner. Factors related
to the degree of synchrony included mutual activities, friendship and
menstrual regularity.
>>>>>>>
Unique Identifier
93288759
Authors
Weller A. Weller L.
Institution
Department of Psychology, Bar-Ilan University, Ramat-Gan, Israel.
Title
Menstrual synchrony between mothers and daughters and between
roommates.
Source
Physiology & Behavior. 53(5):943-9, 1993 May.
Abstract
Menstrual synchrony was examined in three groups of women: 1)
mothers and their daughters; 2) women sharing a room in a private
residence; and 3) women sharing a room in a dormitory. The intracouple
difference in menstrual onset dates was the dependent measure. Mothers
and daughters living in the same domicile displayed a significant
degree of synchrony. Roommates in private residences were also
synchronous, although not significantly more than roommates residing
in dormitories.
>>>>>>>>>
Craig "Not a behavioral endocrinologist, but I play one on Usenet"
Myers
cmy...@mednet.swmed.edu FIDO 1:124/1208
"...[Alice] went on. "Would "That depends a good deal on
you tell me, please, which way where you want to get to,"
I ought to go from here?" said the Cat.
Carla Schack
: into legend. Offhand, I can't think of a plausible evolutionary or biological
: reason for such a phenomenon.
: ba...@rohan.sdsu.edu
well, thanks to everyone who backed it up as fact, and I myself can think
of evolutionary reasons (or at least precident) in my animal behavior
classes they talk about several species in which the females come into
esterous at the same time. it allows births to be coordinated so that
communal mothering and nursing can occur. maybe thats why it might occur
only with friends or co-workers? thanks again for the info.
Steve Klein
>females will tend to have their monthly cycles line up and get into
>weeks after we got there everyone would start at once and we'd all be regular
>people and never anything scientific.
It's called synchronus menstruation, and it was first describedin 1971 by
Martha McClintock. For more detailed information, see pp. 306-307 of MORE
OF THE STRAIGHT DOPE by CECIL ADAMS.
--
Steve Klein phone: 810 YOUR-MAC or 810 968-7622
Your Mac Expert fax: 810 968-2769
Macintosh Consulting e-mail: You...@aol.com
Andy Adsetts
>Offhand, I can't think of a plausible evolutionary or biological
>reason for such a phenomenon.
>-Kate
>ba...@rohan.sdsu.edu
I may be able to help there. My sister is studying anthropology and as
part of her course she came across an article (I know, I know, where's
the cite? :-) about a theory that this dates back to our primitive
past.
Apparently this anthropologist believed that back in the days of Ugh
and Mrs. Ugh and all the other cave dwellers, the two favorite things
to do were to eat and have sex (there being no multiplex cinemas
nearby).
Therefore, when faced with a choice of going hunting for food or
having another quickie with Mrs. Ugh at the back of the cave, you know
which one Ugh would choose. However, there was a particular time of
the month when Ugh was somewhat less interested in Mrs. Ugh than
usual. But what was to stop him from paying a visit to Mrs. Grunt in
the cave next door? (Despite Mr. Grunt that is.) Well, if nature had
it so that the whole tribes women were in sync, those boys would have
no nookie at home and therefore Ugh and his pals would go out on a
hunt for several days to get the food for the next month. The article
even went on to suggest that the reason for the ~28 day cycle was
based on a lunar calendar, and that the best hunting would be with the
full moon, enabling them to hunt during both day and night. (He never
did explain how the women synced with the moon, which made this
theory a bit of a stretch for me.)
The summary of this was that every full moon Ugh and his pals knew the
hunting was good and their women not.
I never really bought the story, but then I can't think of any other
explanation. But does there need to BE an explanation??? I'm not sure.
Maybe I could take this one stage further - perhaps this method did
not have the same effect after a while and nature needed to come up
with additional incentives for Ugh to go hunting. The result : PMS
Mrs. Ugh : I've had enough! You leave your pointy sticks and sharp
rocks all over the cave, you have all your pals over to watch the cave
painting championships, and don't think I haven't seen you looking at
Mrs. Grunt in the morning. And don't think I've forgotten the time you
set fire to mother last year.
Ugh : I'm going hunting. I'll be back in a few days.
Mrs. Ugh : That's right. Walk away when I'm talking to you. Well, you
get your butt out of this cave, you lump of dinosaur lard and don't
come back without a wooley mammoth!!
Andy " when a woman appears to be suffering from PMS, never EVER
suggest that this is the case" Adsetts
JOHN R. SEMPLE
>Carla Schack <csc...@emerald.tufts.edu> wrote:
>>
>>mostly a question for females or doctors, but does anyone have supporting
>>synch?
>
>evidence both for and against this happening. It is amusing to do a
>medline search under the keywords menstrual synchrony, and read the
>varied accounts in the abstracts you find.
>
>It looks like the jury is still out, but there are plenty of studies just
>in the last few years (and this has been looked at for a long time) that
>support both points of view.
I looked through some of these abstracts posted under this thread, and
there's a discrepancy from the version of this I heard that might explain
the conflicting answers.
The way I heard the synchronous menses thing was that pheremone
production would increase at the start of the menstural cycle (kinda
makes sense, if pheremones are to attract sexual mates). These pheremones
would "trigger" the cycles in other women. (Why? Je ne sais pas.) But
pheremones being as weak as they are, I'd think just two women roommates
wouldn't provide the time or concentration that might be necessary (I
know the only time *my* roommate and i were in the same room together was
when we were asleep!). Ditto even with lesbian couples (probably
spend only half the day together, and even then it's only one person. The
synchronous situation I heard was in a convent, which makes more sense...
lots of women concentrated into one place, together for nearly the entire
day. Seems a lot more conducive to the concentration of pheremones, and
synchronization of cycles.
As pheremones are still somewhat mysterious and have rumored effects on
others (opposite sex, especially), I've always thought it was possible,
if not likely. No disparaging comments on my gullibility, please.
Or maybe we're just fascinated with the ability to affect others from a
distance (wearing pheremone scents will make you primally irresistable to
the opposite sex; pheremone scents will synchronize a group of menstural
cycles). Kinda like smell telepathy.
- John "Why, yes, I *am* wearing Jovan Musk...why do you ask?" Semple