Design by Allison Yih.

Gender differences in emotional variability between men and women are negligible, a new University of Michigan study has found. Historically, women have been excluded from medical research partly due to the assumption that ovarian hormone changes lead to emotional fluctuations.

The study tracked self-reported emotion ratings from 142 participants every day over 75 days through an online survey. There were five groups of participants: men, women with regular menstrual cycles and women using three different types of oral contraceptives. The study concluded that across all groups, emotional variability was similar on average. 

Dr. Adriene Beltz, U-M assistant professor of psychology and lead researcher of the paper, said her team was interested in how emotion fluctuates on a daily basis. 

“Our study isn’t saying that hormones don’t matter for emotion,” Beltz said. “What our study shows is that hormones don’t lead to higher highs or lower lows or more variation than all of the other things that as humans lead to emotion variation for us.”

According to Beltz, the assumption that female hormones lead to emotional fluctuations has historically served as an excuse to exclude women from participating in research. Beltz said the study emphasizes the lack of evidence for this assumption. She said she hopes research about gender in medical studies continues and this paper is a first step in the right positive direction. 

“We are just beginning to scratch the surface of the importance of gender, gender variation and gender flexibility in research broadly,” Beltz said. “So I hope that this study is an early step that continues to move us in that positive direction.”

Dr. Alexander Weigard, assistant professor of psychiatry in Michigan Medicine and co-author of the paper, also commented on the gender stereotype that affected scientific literature. Weigard said the notion that women have more emotional variability than men has been assumed rather than tested, and their goal was to test to what extent this assumption was true. 

National efforts have already been implemented to ensure women and minorities are included in research. The National Institute of Health, for example, mandated in 1993 that all NIH-funded clinical research must include women.

“These guidelines are great (and) we’re big fans of (them because they) are making sure that research is inclusive,” Weigard said. “If you’re doing a study, you have to justify why you might not be included in the group and we’re basically saying there’s not a lot of evidence for this being an appropriate justification for excluding females from any kind of research that has to do with emotions.”

According to Beltz, the study included three groups of women using different types of oral contraceptives to see if different hormones and their doses will impact emotion.

“For the most part, variations among those women using different types of oral contraceptives were very similar to naturally cycling women,” Beltz said. “That at least took some credibility away from the notion that there’s something about ovarian hormones that are increasing this variability.”

Rackham student Dominic Kelly, a graduate student working in Beltz’s lab, said this study is unique compared to other development studies in psychology because it uses an intensive longitudinal study rather than a traditional longitudinal study.

“Instead of testing sporadically over a long period of time, you tend to test very intensively over a short period of time,” Kelly said. 

Kelly also said the intensive longitudinal design is an exciting way to complement other types of designs, and the technology development makes the intensive longitudinal design more feasible. 

Researchers are able to measure real-time fluctuations with the intensive longitudinal design, Weigard said. Other methods, like retrospective reports, can be inaccurate because people have a hard time remembering their emotions over the past week or month. Weigard also acknowledged that it’s difficult to get people to finish research tasks on a daily basis and keep them in the study.

The research team has several ideas for future directions to expand on this study. Weigard said one of their ideas is to figure out the contextual and environmental factors that are related to emotion variation and how these factors interact with sex differences. Beltz also added that moving forward, she is interested in understanding individual differences.

“Sometimes averages don’t represent individuals well,” Beltz said. “For some of us, our sex and gender aren’t salient. For some of us, it’s incredibly salient. So how do we figure out individual differences and individual consequences of things like emotion to kind of facilitate everyone’s unique emotional health?”

Amy Loviska, another co-author of the paper and a current graduate student at Purdue University, said a good next step could be to include non-binary individuals.

“If we’re advocating for diverse samples, it’s important to include those voices and those perspectives,” Loviska said. 

Beltz also said they wished they had included participants of various gender identities and different racial and ethnic backgrounds. This current study used a sample of participants who were “young, White, non-Hispanic, and affiliated with a university,” according to the paper. 

“This is just the first step. It’s an important one,” Beltz said. “But we need more data from more people representing more types of experiences.”

Beltz said that we should acknowledge that although people have unique emotional lives, emotional fluctuations are actually quite similar. The gender biases that have been previously prevalent in research need to be removed, Beltz said. 

“Emotion variability isn’t something that should be used to define any one group of people,” Beltz said. “Some emotional variability is common to all of us. It’s part of being human.” 

Daily News Contributor Jingqi Zhu can be reached at