Points of Contention

The September 2002 issue of Comparative Psychology contains the following three articles:

1. Menstrual Synchrony Can Be Assessed, Inherent Cycle Variability Notwithstanding: A Reply to Schank (2001)

-- Aaron Weller, Department of Psychology, and Leonard Weller, Department of Sociology, Bar Ilan University

2. Methods for Obtaining Menstrual Cycle Data in Menstrual Synchrony Studies: Reply to Schank (2001)

-- Cynthia A. Graham, Department of Psychology, Indiana University

3. A Multitude of Errors in Menstrual Synchrony Research (Replies to Weller and Weller, 2002, and Graham, 2002)

-- Jeffrey C. Schank, Department of Psychology, University of California, Davis

The first two articles are replies to the 2001 article by Schank mentioned earlier in this MOLTXIBIT. In turn, the third article is Schank's 2002 reply to Weller and Weller's and Graham's 2002 replies to his (Schank's) earlier 2001 article.

Confused?

That happens when nonspecialists (at least this curator) lacking a solid statistical background attempt to read and comprehend journal articles written by menstrual synchrony experts.

However, it would be safe to say that the majority of women who believe in menstrual synchrony rely on the "WMBS phenomenon" described earlier in this MOLTXIBIT. Using only a slightly more sophisticated statistical method, this MOLTXIBIT in turn relied on two tape measures to demonstrate that menstrual synchrony is impossible when menstrual cycles are not integer multiples of each other, as first pointed out by Winfree (1980).

But menstrual synchrony experts, starting with McClintock in 1971 and on down to the authors of the three above-mentioned articles, use an array of statistical methods: Monte Carlo computer simulations, binomial probabilities, standard deviations, random control groups, t-tests, U-tests, group means, median intra-family cycle length differences, specific sampling methods, and so on.

What follows is a brief discussion of some points of contention between those experts who believe menstrual synchrony to be a real phenomenon, and those who believe it to be "statistical artifact."

MOLT encourages those who are interested in getting to the bottom of the menstrual synchrony debate, to contact your "friendly neighborhood statistician," whether at a local college or business, to see if they might discuss some of the relevant statistical issues with you. Or better yet, take a few courses in statistics!

Simply relying on the WMBS phenomenon in deciding that menstrual synchrony is real, is no different than relying on the fact that the street outside your house is flat, in making up your mind that the earth as a whole is flat.

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