It’s been well-established that experiencing sexual harassment has a negative effect on women. But what about witnessing it?

A new study from University of Connecticut researchers Stephenie Chaudoir and Diane Quinn suggests that simply being a bystander to sexism is enough to inspire women to report higher identification with women as a group, and heightened feelings of negativity toward men. The effects of this “bystander sexism” help to explain how a cat-call targeted at one woman can work to demean all of us.

In the study, the researchers asked 114 female college students to watch one of two videos and imagine themselves as a witness to the scene that unfolds. In the first version, a man approaches a woman and says, “Hey Kelly, your boobs look great in that shirt!” In the second, the man greets the woman by saying, “Hey Kelly, what’s up?” Study participants then completed a survey designed to show how strongly they identify themselves with women as a group, how much anger and fear they feel toward men as a group, and how likely they are to be prompted to either “move against” or “move away” from men in general.

The result? Even though women only graded the “boobs” comment as a “moderately prejudiced” thing to say, women who witnessed the harassment were more likely to identify as women, feel anger toward men, and express the desire to “move away” from men.

The fact that street harassment tends to divide men and women as classes is no secret. Women who have experienced street harassment often report coping by responding with wariness to all strange men, in order to fend off possible future harassment. And men express frustration that they can’t approach a woman in a way they perceive as non-harassing—-whether it’s to ask for directions or deliver a compliment—-without being regarded as a potential offender. But the defensive strategy is often made necessary by the frequency of such harassment; Chaudoir and Quinn note that  “42% of U.S. female college students [report] that they are the direct targets of cat-calls at least once a month.” And this casual sexism has serious effects on its victims: “the experience of street harassment is directly related to greater preoccupation with physical appearance and body shame, and is indirectly related to heightened fears of rape for U.S. undergraduate women.”

What the new study reveals is that harassment also has serious effects on women who are not victims—-and men who are not harassers. “It makes sense that if women feel like they have been discriminated against, or that specific men are engaging in sexist behaviors that can harm them, they’re going to be on high alert in the future from other men, even if those men have no intent of participating in the discrimination,” says Chaudoir. For the men, “our data do speak to this unfortunate predicament where men who are not harassers and men who are not doing anything wrong end up being painted in the eyes of women, at least for some period of time, in a negative way,” Chaudoir says. “For men who are doing nothing wrong, these [harassers] may be shaping the ways that they’re being perceived as well.”

Despite the depressingly divisive results here, this study shows that men and women alike have an investment in working to eliminate sexual harassment. As Chaudoir and Quinn’s work demonstrates, harassment against women often occurs in public and in view of plenty of bystanders, male and female. We all have the opportunity to make it clear that this sort of behavior is unacceptable.