Discussions of gender inequality in the workplace often focus on the more visible manifestations of the imbalances between men and women: wage inequality, the motherhood penalty, or the lack of paid leave. These are all important issues that, if fixed, would help women. More difficult to pinpoint and address, however, are the ways that what sociologists call “emotional labor” also reinforces workplace gender inequality.

A key feature of the modern economy—and a way work has deviated from what it was in the past—is that the outputs of many jobs have become invisible. In her seminal book The Managed Heart, the sociologist Arlie Hochschild describes how the transition from a manufacturing-based economy to a service-based economy has brought on the commodification of emotions. Hochschild’s argument is that in service jobs, workers do not produce tangible commodities like they did in manufacturing positions. Rather, they are required to provide “good service.” The ways that this phrase becomes defined and mandated means that organizations expect workers to create and sell emotional states in themselves and in others. This introduces a host of questions, like who “owns” emotions when organizations can require workers to feel happy, pleasant, and congenial in order to earn their paycheck?

Hochschild focuses on the work done in the airline industry. She documents the ways flight attendants sell a certain emotional experience to flyers. Rather than simply offering drinks and peanuts, they have to ensure that passengers feel cared for and safe. They muster feelings of deference, and suppress any feelings of irritation, annoyance, and anger that might emerge in response to demanding or rude flyers. Other professions mandate other feelings: Bill collectors, for instance, are encouraged to emote belligerence and combativeness in order to compel debtors to pay up.

These divergent emotional norms are significant because they can reproduce gendered inequalities. As Hochschild notes, the fact that women are required to generate traditionally feminine emotions while men do the opposite furthers the idea that certain occupations are “for men” or “for women.” Thus, being a flight attendant becomes seen as a “natural” job for women, given the expectations of nurturing attached. Meanwhile, being a pilot or an air-traffic controller may not seem such an obvious fit.

Emotional labor in the airline industry also has adverse consequences for minority workers, though these develop through a different mechanism than what Hochschild describes in her book. In a study of black pilots and flight attendants, the sociologist Louwanda Evans observed stressful, near-constant emotional labor in response to racist remarks from colleagues and passengers. For instance, one white female passenger approached a black pilot to explain that she was afraid to fly with him because, after seeing commercials for the movie Soul Plane, starring Snoop Dogg, she had become convinced that he’d pilot the plane like a marijuana-smoking rapper. And then there was the passenger in the gate area who said, “That nigger better not be flying my plane.” On top of this, black airline employees report being subjected to extensive questioning by their coworkers to prove their competence.

Because airlines do not have procedures in place to address the distinctive, racialized challenges faced by workers of color, these employees are left to do a great deal of extra emotional labor on their own—sometimes in response to the statements and behaviors of others in the organization.

Emotional labor is of course not limited to the airline industry. Jennifer Pierce, a University of Minnesota sociologist, found that the expectations for emotional labor in the legal profession apply to women working in every part of the field. In other words, while male attorneys—generally speaking—are allowed and even expected to be aggressive and domineering, that does not extend to female attorneys, who are frequently penalized if they attempt to conform to these emotional norms. Meanwhile, female legal secretaries described expectations that they would be deferential and caretaking towards (mostly male) attorneys, but male secretaries were not subject to the same norms. Thus, even when women worked in male-dominated positions, the emotional expectations deemed “appropriately” feminine still applied in ways that made it more difficult for women to do their jobs. Once again, the hidden component of this work renders it less visible but no less taxing.

On the face of it, emotional labor can seem something normal and commonplace in an economy where service jobs are so ubiquitous. But as a lot of research shows, the pressure to produce and manufacture certain emotional states can be more draining for some employees than others. When thinking through various workplace inequalities, such as wage gaps and a lack of diversity in certain occupations, it’s just as critical to consider how important unseen labor is in shaping how work gets done, and who gets to do it.