A woman's menstrual cycle has no effect on her ability to think

New study into the link between cognition and menstruation dispels the myth that women are unable to make consistent and rational decisions at work.

It has long been a commonly held belief that women’s cognitive abilities – like memory, attention, and problem-solving – change depending on where they are in their menstrual cycle.

However, a new study by Melbourne Business School Assistant Professor of Management Daisung Jang has demonstrated there is absolutely no link between cognition and menstruation.

The study reviewed over 100 scientific papers, totalling nearly 4000 participants, that looked at the relationship between the two. In each study, women completed cognitive tests with objective answers, across multiple phases of the cycle.

“What we found, when using robust methods to determine the menstrual cycle, is that there is no relationship between decision-making and menstruation,” Assistant Professor Jang said.

The findings challenge the stereotype that women may not be fit to perform some roles and will hopefully prevent women from being unfairly judged based on their biology.

“It dispels a myth about the cycle and this common stereotype that women, at certain phases of the cycle, are more or less reliable,” he said.

Symptoms of mental health are not indicative of cognition.

There is no doubt that women experience varying symptoms at different points of their cycle, including mood swings, fluid retention, and changes in appetite.

In certain cultures, these negative effects have led to women being marginalized in workplaces.

“The sanctions can be extreme,” Assistant Professor Jang said.

“At parts of the cycle, women might not be allowed to do certain work because they are considered unclean.”

The cycle’s effect on mood has also led to many women being unfairly judged as incapable of holding certain positions.

This was evident during the 2008 election when Hillary Clinton’s candidacy was undermined because it was claimed she wouldn’t be able to make sound decisions.

A similar thing was seen more recently when Kamala Harris ran against President Trump.

Assistant Professor Jang confirms that while there is certainly a link between mental health and menstruation, this doesn’t affect a person’s ability to think.

“Previous studies have found that women are more likely to have mental health issues pre and post cycles – we’re not disputing that,” he said.

“But symptoms of mental health are entirely separate from cognition. Over time, the two concepts have become conflated.

A woman’s mind, in this capacity, is no more variable than a man’s.”

Science over self-reporting

To ensure scientific rigor, Assistant Professor Jang and his colleagues examined studies with stringent specific criteria.

“Firstly, women had to be measured at multiple times in a cycle,” he said.

“The measures of cognition also had to have objectively right or wrong answers.”

Examples included IQ tests, looking at measures of attention, spatial and verbal ability, and fine motor skills.

They made their conclusions based on studies that used objective methods of cycle assessment, such as hormone assays.

The results showed no difference in the participants' results as they moved through their cycles.

Assistant Professor Jang is hopeful that the findings will help remove stigmas and reduce bias in hiring and promotion practices.

“Women’s contributions at work – and elsewhere – should not be minimized,” he said.

“The menstrual cycle isn’t really studied in management literature and yet due to longer life spans and more access to calories, women are having more periods than ever before.

To promote equality, we need to understand it.”

The paper was published in PLOS ONE and co-authored by Assistant Professor Jack Zhang from the Nanyang Technological University and Professor Hillary Anger Elfenbein from Olin Business School.

View the full paper ‘Menstrual cycle effects on cognitive performance: A meta-analysis’.

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