Multiple influences on menstrual synchrony: Kibbutz roommates, their best friends, and their mothers

Abstract

Menstrual onset dates of women living in kibbutzim were compared with those of their roomates, their best friends in the kibbutz, and their mothers. Since these three groups of women constitute the overwhelming number of the subjects' female interactions, this enabled the examination of multiple influences on menstrual synchrony. Synchrony was found between roommates and between best friends, but not between mothers and daughters. The relationships of friendship and joint activities to synchrony were also analyzed. The findings support a pheromonal, and not an environmental, explanation of menstrual synchrony. © 1993 Wiley-Liss, Inc.

Possible evolutionary origins of human female sexual fluidity

“…Over the course of an academic year from October to April, 135 close friends and roommates in a dormitory gradually synchronized their menstrual onsets. In the last 40 years, since McClintock's groundbreaking study, a large number of studies have independently confirmed menstrual synchrony among women who live or socialize together (Skandhan et al , ; Graham & McGrew, , ; Russell, Switz & Thompson, ; Quadagno et al , ; Preti et al , ; Goldman & Schneider, ; Matteo, ; Little et al , ; Graham, ; Weller & Weller, , , b, ; Weller, Weller & Avinir, ; Stern & McClintock, ; Weller et al , 1999 a ; Weller, Weller & Roizman, 1999 b ). However, an equally large number of studies have failed to find menstrual synchrony under similar circumstances (Wilson, Kiefhaber & Gravel, ; Trevathan, Burleson & Gregory, ; Weller & Weller, 1995 a,b , ; Cepicky et al , ; Strassmann, ; Yang & Schank, ; Ziomkiewicz, ).…”

Menstrual synchrony under optimal conditions: Bedouin families.

“…A number of studies have examined whether women who engage in more joint activities would be more synchronous (Jarett, 1984;A. Weller & Weller, 1992, 1995a, 1995bL. Weller & Weller, 1993b;, because women who spend more time together would also be expected to be exposed to greater mutual pheromonal influences.…”

“…Weller & Weller, 1992, 1995a, 1995bL. Weller & Weller, 1993a, 1993b. Two noncompeting explanations have been offered as to why friends show greater synchrony than nonfriends.…”

Evolutionary psychology and perfume design

“…More than 30 years ago, McClintock ( 1971 ) noted in her classical paper that cohabitating female students tend to synchronize the onset of their menstrual cycle. This early observation gave rise to several dozen studies on highly variable samples of cohabiting women, such as among mothers and daughters (Weller and Weller 1993a ), Bedouin families (Weller and Weller 1997 ), kibbutz shared households (Weller and Weller 1993b ) or lesbian couples (Weller and Weller 1992 ). A majority, but not all (Trevathan et al 1993 ;Yang and Schank 2006 ) of the studies showed similar shifts toward menstrual synchrony.…”