The relationship between hormonal changes and women’s political attitudes has sparked a debate among researchers. Research published last year in Psychological Science found that women’s menstrual cycle influenced their religious and political orientation differently depending on their relationship status, but a replication of the study casts some doubt on those findings.
The two-part study by Kristina M. Durante of the University of Texas at San Antonio and her colleagues found that single women tended to become more socially liberal, less religious, and more likely to vote for Barack Obama during the ovulatory phase of the menstrual cycle. Women in committed relationships, on the other hand, tended to become more socially conservative, more religious, and more likely to vote for Obama’s opponent Mitt Romney.
In an article published February 25 in Psychological Science, Christine R. Harris of the University of California at San Diego and Laura Mickes of Royal Holloway, University of London said many menstrual cycle studies where flawed because the measures of fertility used were imprecise.
For their study, Durante and her colleagues predicted each participant’s day of ovulation by having them report the start date of their last menstrual period and the previous menstrual period, along with the expected start date of their next menstrual period, and the typical length of their menstrual cycle. Based on this information, the participants were lumped into either a high-fertility group or a low-fertility group.
Harris and Mickes also said the findings of the study defied conventional wisdom.
“The findings depart strikingly from common-sense ways of thinking about political and religious behavior, implying markedly greater fickleness in women’s attitudes relative to those of men—something that, to our knowledge, has not been noted by pollsters and political scientists,” they wrote.
In a study of 1,206 women, Harris and Mickes attempted to replicate the findings of Durante and her colleagues. The researchers failed to find a statistically significant effect of ovulatory status and relationship status on either religious beliefs or social political attitudes. They also failed to find a statistically significant effect of ovulatory status and relationship status on hypothetical voting and actual voting behavior.
“This study adds to a growing number of failures to replicate several menstrual cycle effects on preferences and attraction, which invites concerns that this literature as a whole may have a false-positive rate well above the widely presumed 5%,” Harris and Mickes wrote.
Responding to their article, Durante and her colleagues objected to the allegation that they ever suggested women were more “fickle” than men when it came to political attitudes.
“Harris and Mickes offer a grossly misleading portrayal of the context for our research,” they wrote in their response, which was also published in Psychological Science. “The view that women are somehow more fickle in their decision making than men is false and was never the impetus for this research.”
Durante and her colleagues also claimed that the replication study did, in fact, produce statistically significant results when the pre- and postelection (hypothetical voting and actual voting behavior) data were added together.
“Harris and Mickes’s defense of the null hypothesis despite finding near-significant interactions in two samples and a significant interaction when the data were combined is puzzling,” they wrote.
Durante and her colleagues concluded that it “should not be surprising that women’s behavior, like men’s, is influenced by hormones,” and called for additional research on this “novel pattern” of behavior.