In the cascade of sexual-harassment allegations now coming to light, a central question has emerged: Why did so few speak up before?

Research from psychology provides an answer: Many women feel complicit in their own assault and are ashamed that they did not react more forcibly at the time. Consider the experience of the actress Rachel McAdams, who as a 21-year-old theater student was lured by the director James Toback to a hotel room and pressured to take off her clothes. McAdams, now 38, kept quiet about the episode for 17 years. “This has been such a source of shame for me—that I didn’t have the wherewithal to get up and leave,” she told Vanity Fair.

Like McAdams, many people feel embarrassed that they “let” themselves be sexually harassed, and they keep quiet as a result. Yet according to research from psychology, finding the resolve to get up and leave is much harder in the moment than it seems after the fact.

A study conducted at Boston College in the 1990s sheds light on this issue. Psychologists Julie Woodzicka and Marianne LaFrance asked nearly 200 women what they would do if, during a job interview, they were asked questions like, “Do you think it is important for women to wear bras to work?” and “Do people find you desirable?” These questions were chosen because they were clearly sexually harassing.

Most women thought they would be angry and confrontational if an interviewer used these lines on them. They said they would storm out, tell the interviewer to shove off, or, at the very least, refuse to answer his inappropriate questions. Some said they would report him to his supervisor.

But what do people do when actually subjected to sexual harassment? To find out, the researchers placed advertisements in newspapers and posted fliers around campus advertising a position as a research assistant in a psychology lab. They recruited 25 women to come in for what appeared to be a job interview. The researchers trained a male actor to pose as the interviewer and to subject each woman to the sexually harassing questions. The researchers covertly videotaped the interactions.

(This study was able to get the green light from a research ethics board, according to the first author, because the research team thoroughly “debriefed” the participants after the study was over, paid them, and gave them the option of withdrawing their data; only one person asked that her videotape be erased.)

Over the course of the study, the actor sexually harassed 25 women in an identical manner. He was never reported.

What happened when the interviewer asked the harassing questions? Not a single woman walked out of the interview. The videos showed that the women, smiling uncomfortably, answered the harassing questions, without challenging the interviewer. At most, they tried to pivot after responding, to refocus the interview on substance. A few (nine, or 36 percent) asked the interviewer why he had asked such personal questions, yet all but two of these women waited until the end to do so, when they were invited to raise any questions they had. Tellingly, not a single person filed a complaint or reported the interviewer. Over the course of the study, the actor sexually harassed 25 women in an identical manner. He was never reported.

There was, in other words, a huge gulf between what people did and what people thought they would do in response to harassment. The researchers went in search of an explanation. They found that the women who contemplated the situation hypothetically imagined they would feel angry, but women who were put through the experience reported feeling afraid. Their fear prevented them from confronting the harassment.

Psychologists have a term for this disconnect: an “affective forecasting error.” We have immense trouble knowing how we will feel in response to a stressful situation. As a result, we misjudge what behavior would be a normal response. In particular, we imagine people will be more assertive and confrontational than they typically are.

What are the consequences of this prediction error in cases of sexual harassment or assault? Many victims are like McAdams: They blame themselves for not having “the wherewithal to get up and leave.” She said that she has felt shame for nearly two decades, because she should have reacted more assertively in the situation in the hotel. Yet what McAdams did is normal. It seems that our affective forecasting errors lead us to blame victims for failing to exit harassing situations, because we incorrectly believe that if it happened to us, we would have marched straight to HR.

Our affective forecasting errors lead us to blame victims for failing to exit harassing situations, because we incorrectly believe that if it happened to us, we would have marched straight to HR.

This psychological bias also leads us to doubt the veracity of victims’ claims. When Anita Hill testified that Clarence Thomas sexually harassed her as her supervisor at the Department of Education, many who heard Hill’s story thought, “If what she says is true, surely she would have reported Thomas immediately, as any sane person would have. Surely, she would not have followed him to her next job. She must be lying, because her behavior is not consistent with how a normal person would react to harassment.” Yet her behavior is perfectly consistent with how normal people react to harassment. The Boston College study confirms this.

Yes, the Boston College study was conducted in 1998, and there are questions about whether the same findings would hold true today. It’s possible that more women would feel empowered to push back, walk out, or file a report against the harasser. It’s also possible that those of us sitting in judgment would show greater appreciation for how difficult it might be for victims to come forward. Now that so many women have shared their feelings of fear and shame following harassment, it may make us more empathetic. It may make us less judgmental toward victims who stay silent.

On the other hand, the wide gap between what people think they would do and what people actually do is one of the most fundamental phenomena in all of social psychology.

As social animals, we are strongly motivated to maintain group ties and preserve social harmony. We hate to stand out, violate social scripts, break face, or risk embarrassment. Yet at the same time, the power of these unwritten social rules remains invisible.

The problem is, in our culture that idealizes individualistic autonomy, we tend to think that people shouldn’t care about creating awkward situations or disrupting social norms. We expect people to disobey immoral orders, refuse unreasonable requests, and break away from their peers when the group is doing something wrong. We think people should be confrontational when the situation calls for it.

Yet these expectations defy our social psychology; they ignore our fundamental need to belong to our community. (Some research shows that people from less individualistic cultures are less prone to these social prediction errors, possibly because they recognize that community members are motivated to act in ways that promote social harmony.)

The reasonable-person standard pervades the law yet ignores the gulf between what uninvolved parties think is normal and what actually is.

The silence of sexual harassment victims can be understood as a particularly gendered manifestation of this broader social psychological phenomenon. There is a large disconnect between what people think they would do in idealized versions of their individualistic selves and what people actually do—as they are embedded in social relationships and communities and affected by cultural norms that prescribe roles and dictate appropriate social behaviors.

This disconnect is generally ignored by our laws, which entrench the problem. Our legal system frequently asks jurors to apply their ordinary sensibilities to determine what a “reasonable person” in their community would do in response to a given situation. This standard invites them to rely on their faulty assumptions about social behavior to pass judgment on others, such as complainants who wait years to report sexual harassment or assault.

It applies, for instance, to Title VII workplace sexual harassment cases. Employees who “unreasonably fail to take advantage of corrective opportunities” provided by their employer, such as failing to report the incident using formal grievance procedures, have no legal recourse for the harassment they suffered. In one case, a waitress who waited 17 days to report her supervisor’s serial sexual harassment was deemed to have acted “unreasonably” in waiting so long.

The reasonable-person standard pervades the law yet ignores the gulf between what uninvolved parties think is normal and what actually is. We must recognize this gulf and treat victims with the sympathy, patience, and understanding they deserve.