What would you do if you saw a woman being abused? Would it matter if she were a prostitute?

What would you do if you saw a woman being abused by her boyfriend?

That was the question posed by a recent episode of ABC’s candid camera social experiment show, “What Would You Do?”

The producers sent an actress, made up to look badly bruised, into a diner and filmed the reactions of her fellow patrons when her “boyfriend,” also an actor, followed her inside and began insulting and yelling at her.

When he became physically violent, grabbing her wrists and leaving no doubt in patrons’ minds that he had inflicted those bruises, they sprang into action. Diners of both genders came to the woman’s defense, urging her to leave the diner with them or confronting her boyfriend about his behavior.

Changing the race of the actor and actress from white to black elicited much the same reaction, though diners were slower to act when the woman and her “boyfriend” were black.

Then the producers changed another variable: What the woman was wearing. In the first two scenarios the actress was dressed in jeans and a T-shirt. In the second two scenarios, the same actresses were dressed provocatively, in low-cut dresses. And in those latter instances, regardless of the woman’s race, no patrons intervened to stop her boyfriend from abusing her. Two fellow diners – women – looked on, speculating in whispers that the bruised woman being verbally and physically abused just feet away from them might be a prostitute.

Last month at a conference at Harvard University, I spoke on a panel about what we in the feminist community call “slut-shaming.” Slut-shaming, the practice of reviling women for even appearing to be sexual, runs rampant in our culture. Women are expected to walk a fine line when it comes to sexuality: They have to be sexy, of course, but if they’re too sexy, they’re punished for it.

We see that punishment in pop culture: In horror movies, the women who have sex are brutally murdered, while the virginal woman tends to live. We see it in politics: Remember the media firestorm when Hillary Rodham Clinton showed “too much” cleavage, and when Sarah Palin posed for a magazine cover in running shorts? (There was no such firestorm when photos surfaced of Massachusetts senatorial candidate Scott Brown posed, naked, in Cosmopolitan magazine). And of course, we see it in our own daily lives: Who hasn’t been called, or thought of someone as, a slut at least once?

People who slut-shame believe that a woman who wears a low-cut dress, or behaves in any way that suggests that she is a sexual being, is less valuable than other women. The mere suggestion of sex, makes her dirty; less worthy of our respect; and more deserving of our insults, mockery, and violence. She deserves whatever she gets, we reason, because she chooses to act in a way that devalues her as a person.

The scene that unfolded in that diner as the hidden cameras rolled was an example of the real-life consequences of this. Being called a name in high school hurts a girl’s feelings and threatens her reputation, and it’s an experience no one deserves. But once we leave high school, once we take our attitudes about women, sex, and human worth out into the world, the stakes get higher. What happened in that diner was an example of the very real, potentially life-and-death, consequences of the belief that women who are sexual are less deserving of basic human rights.

Nowhere is this belief more evident than in the way our culture treats women who do for a living what the rest of us do in private. When asked why they didn’t intervene, the two women who suspected that the victim of abuse in the diner might have been a prostitute offered those suspicions as an explanation.

They believed that because she might have been a sex worker, she wasn’t worthy of their concern or effort, and were perfectly comfortable saying as much on the record as the camera rolled. But as one of the actresses asked afterward, what difference should it make if she were a prostitute?

Why should it make her less deserving of the intervention that was offered to a more modestly dressed woman? Regardless of how you feel about prostitution, or about low-cut dresses, all women deserve to live lives free of violence.

The attitudes expressed by those two women are common, says Audacia Ray, a sexuality rights activist, co-founder of Sex Work Awareness, and a former sex worker herself. “Sex workers generally aren’t treated as whole human beings worthy of dignity and respect in American culture,” Ms. Ray told me.

And as the scene in that diner demonstrated, the mere suspicion that she is a sex worker is enough to disqualify a woman from that, and from the potentially life-saving intervention that patrons were prepared to make for a more modestly dressed woman. And lives are at risk: According to the National Coalition Against Domestic Violence, almost 1 in 3 female homicide victims whose deaths are reported to the police are killed by an intimate partner.

"Sex worker" is a term that encompasses a range of occupations, not all of which are illegal. Not all lawbreakers deserve our respect, of course, but what makes people in America so willing to disrespect prostitutes is that they sell sex. The way we treat prostitutes is simply an extreme manifestation of the way we treat all women who are publicly sexual. I don't advocate breaking the law, but I do advocate treating all human beings with respect.

There is nothing a woman can do, no dress she can wear, no job she can work that makes her more deserving of violence. Perhaps you haven’t been in a diner and witnessed domestic violence happening just a few tables away from you.

But domestic violence is happening right under your nose, and all around you: One in 4 American women will experience domestic abuse in her lifetime. That’s 1.3 million women a year.

The question, then, shouldn’t be “What would you do?” The question is, “What will you do?”

Chloe Angyal is a writer from Sydney, Australia, who now lives in New York.