Women tend to report greater fatigue than men, yet observers see them as less tired

In a new study published in Sex Roles, researchers have identified a striking gender bias in how fatigue is perceived in others. Observers evaluating short video clips of men and women engaged in social interactions consistently underestimated women’s fatigue levels while overestimating men’s, compared to self-reported levels of fatigue by the individuals in the videos. This phenomenon suggests deeply rooted societal stereotypes may influence perceptions of health and wellbeing.

Fatigue is a common and debilitating condition, affecting up to 45% of adults and creating significant societal and economic burdens. Chronic fatigue can reduce household productivity by 37% and labor force productivity by 54%, with estimated societal costs in the United States ranging from $9.1 to $24 billion annually. Understanding how fatigue is perceived in others is critical for improving empathy, healthcare outcomes, and interventions for individuals suffering from persistent exhaustion.

“I first became interested in this research as a graduate student after seeing a grant call from the Maine Space Grant Consortium for aerospace-related studies,” said study author Morgan D. Stosic, a research psychologist at KBR working in the Behavioral Health and Performance Laboratory at NASA’s Johnson Space Center.

“While reviewing the literature on human performance in space, I was surprised to learn that fatigue accounts for half of all accidents and errors in space missions and aviation. Coming from a background in nonverbal behavior research, I started wondering if we could identify behavioral markers of fatigue, such as slumped posture, greater fidgeting, or reduced facial expressivity.”

“I also wanted to explore whether outside observers could accurately detect how fatigued someone was based only on their behaviors. As the project evolved, however, our focus shifted more to the applied health side of fatigue expression and perception, particularly to the differences in how men’s and women’s fatigue is perceived by others.”

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The researchers conducted two separate studies to examine perception of fatigue. In Study 1, they began by recording video clips of men and women engaged in social interactions. Participants were paired in dyads and asked to discuss shared interests during five-minute conversations conducted over video conferencing. Afterward, each participant self-reported their fatigue levels using a validated measure.

From these recordings, 10-second clips were extracted at random points from the interactions. A separate group of 71 perceivers was recruited to watch these silent clips and rate the targets’ fatigue levels based on their nonverbal behavior. These perceivers had no additional context about the individuals they were rating. To explore potential mechanisms behind any observed biases, the researchers also analyzed nonverbal cues, such as posture, facial expressions, and attentiveness, displayed by the targets in the videos.

The findings showed a gender bias in the perception of fatigue. Observers consistently rated women as less fatigued than men, even though women reported higher levels of fatigue on average. Additionally, the researchers found that women appeared more expressive and attentive than men, which may have contributed to the perception that they were less fatigued. Importantly, this expressiveness was not tied to the targets’ actual self-reported fatigue levels, indicating that societal norms encouraging women to display positive affect in social settings likely influenced the observers’ judgments.

While this study provided evidence of a bias, the differing scales used for self-reported and perceived fatigue meant the researchers could not directly compare the magnitude of bias in absolute terms. Study 2 was designed to address this limitation by directly comparing perceivers’ ratings of fatigue with targets’ self-reports using the same scale.

The researchers selected 40 new targets from the same larger repository of video recordings used in Study 1, taking care to avoid overlap with the earlier sample. In this follow-up, both targets and perceivers rated fatigue using a single-item question that asked how much the target was “bothered by fatigue,” measured on a consistent five-point scale. As in Study 1, perceivers viewed silent 10-second clips of targets and rated their fatigue levels. Nonverbal cues were again analyzed to examine their potential influence on perceptions.

The findings confirmed and extended the results of the first study. Observers continued to rate women as less fatigued than men, even though women reported higher levels of fatigue. Furthermore, when the researchers compared self-reports to observers’ ratings, they found that women’s fatigue was consistently underestimated, while men’s fatigue was overestimated.

:Our research found that after watching video clips of men and women interacting socially, observers tended to underestimate women’s fatigue and overestimate men’s fatigue compared to what the individuals themselves reported,” Stosic told PsyPost. “This disparity in judgments of fatigue aligns with other studies showing how women’s health symptoms are often minimized or not believed. This could have real-world consequences in healthcare provision, like leading to mistakes in diagnosing health issues, delays in proper treatment, and even making women less likely to report fatigue for fear of not being believed.”

“On the other hand, overestimating men’s fatigue could result in unnecessary medical tests or overprescribing treatments. Although we did not find any relationships between how fatigued an individual said they were and their nonverbal behaviors (e.g., greater fidgeting, slumping their posture), we did find that observers’ perceptions of fatigue were influenced by how expressive and attentive someone was behaving. Since women tend to behave in more expressive and attentive ways, this explained in part why women’s fatigue was underestimated compared to men’s.”

There are some limitations to consider. For instance, the reliance on self-reported fatigue as a benchmark introduces potential inaccuracies, as fatigue is inherently subjective and can be influenced by individual differences in self-awareness and social pressures.

“In this study, we measured individuals’ fatigue by asking how fatigued they felt on average over the past few weeks,” Stosic explained. “This approach allowed us to capture a more chronic or ongoing level of fatigue, which is likely closer to what someone would report to their healthcare provider, rather than focusing on their current fatigue, which might be more directly linked to operational errors on the job.”

“It’s also important to note that our participants who’s fatigue was being judged were university students and the participants who were judging their fatigue were a mix of university students and online respondents from the general population. It is possible that the high levels of fatigue reported by university students differ in severity from those who seek medical attention for chronic fatigue syndrome or those experiencing fatigue in high-performance related jobs. Additionally, we might observe differing levels of accuracy in perceiving others’ fatigue from individuals whose job might entail perceiving when others are feeling fatigued in order to intervene, such as healthcare providers or fight controllers in mission control.”

This research is the first to reveal that women’s fatigue is consistently underestimated while men’s is overestimated. The findings highlight the need for further study to improve fatigue assessment and treatment.

“I am excited to have recently joined the Behavioral Health and Performance Laboratory at NASA’s Johnson Space Center where I will continue to focus on mitigating human performance risks in spaceflight,” Stosic said. “Building on this research, I aim to further explore how fatigue is expressed behaviorally, so we can better detect it in real-time and find ways to prevent it.”

“As space missions venture farther from Earth and communication delays with mission control increase, relying on one’s crewmates to be able to accurately perceive when someone is experiencing higher levels of fatigue will become critical. Additionally, since our research uncovered a gender bias in how fatigue is perceived, it’s important to create interventions that address this gap and ensure fair, accurate assessments of fatigue across increasingly diverse astronaut teams.”

The study, “Gender Bias in the Perception of Others’ Fatigue: Women Report More Fatigue Than Men But Have Their Fatigue Underestimated by Others,” was authored by Morgan D. Stosic, Erin E. Flynn-Evans, Jennifer Duenas, and Mollie A. Ruben.