Flash drive. Laptop. Phone.

If your home was under attack and you had to flee, what would you take with you?

That's the theme of a new celebrity video highlighting the global refugee crisis. Released last week on Facebook by the , it features 10 actors, including Cate Blanchett, Keira Knightley, Stanley Tucci, Jesse Eisenberg and Chiwetel Ejiofor. And heartthrob Kit Harington from Game of Thrones.

Dressed in black, they sit in front of a screen showing images of refugees and take turns reading lines from "What They Took With Them," a poem by U.K. writer . Her work is inspired by stories from refugees about the items they took when they fled.

House keys. House keys. House keys,one actress recites, urgently at first, then slowly, as if remembering not to forget, while an image of endless rows of white tents in an unnamed refugee camp flashes on screen.

But what is it exactly, that this ad wants us to remember? That 65 million refugees have been forced to flee their homes? That the world must take action on their behalf? Or in the end, is this just another celebrity ad?

Actually, celebrity ads can get people to pay attention to a cause they might previously have ignored. If you recognize any of the actors taking part, the film will have an effect on you, says Richard Petty, a professor of psychology at Ohio State University. He developed the Elaboration Likelihood Model of persuasion, which explains how celebrity ads can change public attitudes around certain issues.

Especially if you're a fan of their TV shows or movies. "Subconsciously, you will think, 'I like them, so I am going to be supportive of whatever they're supporting,' " he says. It may not make you donate to the cause or sign a petition right away, but it "may make you more likely to pay attention to the issue" when you encounter it again in the future, he says.

By using celebrities and launching the film exclusively on Facebook, UNHCR hoped to attract the widest audience possible — and get people to share it across social media. "When we work with [celebrities], we benefit from their voice and profile and reach more people around the world," says Alison Tilbe, who manages UNHCR's engagement with celebrity talent, including Blanchett and the other actors in the film. "What they're doing is amplifying refugee voices."

But raising awareness is just the first step in creating an effective advocacy campaign. "People will ask, 'What am I supposed to do now that I feel sad or angry or afraid?' " Petty says. That means giving viewers something "consequential" to do.

"What They Took With Them," as the video is called, does indeed end with an action.

Right before the video ends, the words "We stand with refugees. Stand with us. Sign the petition now," pop up on the screen in big bold letters.

The petition, launched by UNHCR in June, currently has over 1 million signatures. It urges U.N. leaders to "find solutions for refugees," says Tilbe. "We want people to call on governments to help refugees get an education, find somewhere safe to live, find work and learn new skills so they can make a positive contribution to their communities," she says.

The film and the petition were created to get the public to pay attention to the U.N. High-level Meeting On Refugees and Migrants at the U.N. General Assembly in New York on September 19, says Tilbe. The petition will be delivered to U.N. Secretary-General Ban Ki-moon today.

But not everyone is convinced that signing a petition will make people feel as if they've made a difference. "I don't know if people feel that petitions are 'consequential,' " says Petty.

Jason Wojciechowski agrees. He's a campaign strategist at , an agency that makes creative political campaigns for global NGOs, including those on the refugee crisis. "They tell me to 'Stand with Refugees,' " he says. "As a person who's just been moved by this video and connected with it, I don't know what that really means."

Even though the petition has 1 million signatures, that won't necessarily make an impression on the leaders attending the meeting, he explains. There are 193 diplomats at the U.N., representing each member-state, so no one country will feel a local groundswell of support for the cause. And 1 million is just a small segment of the world's 7 billion.

"In the real world of politics, leaders don't care what a tiny portion of the world thinks. They care about what their constituents think," he says.

Then again, some in the nonprofit world think starting with a generic action, like signing a vague petition, is okay. Amy Sample Ward, CEO of the , a group that helps NGOs with digital campaigns, suspects that the "milquetoast ask," as she calls it, is by design.

"These people have heard of Cate Blanchett, but they don't know you or your organization," she says. "To ask them to do a high-bar action like attend a rally or donate to a cause — that would have a really low response."

Getting signatures on a UNHCR petition is a starting point, says Ward. Now that the agency knows this group of people is committed — and has their email addresses — the UNCHR can send them more information about the refugee crisis, "working them up to a point where they're ready to spend time and money" on the cause, she says. It's a tactic that campaigners call "list-building" or "momentum-building," she explains.

Still, some campaigners think that the film was a lost opportunity — it put people on an emotional high, but didn't translate to a meaningful action. Because the UNHCR is an agency of the U.N., it does not have any real power to make change. "As the U.N., you can't vilify the governments who are also the ones giving money to UNHCR to support campaigns," says Wojciechowski. "That's not what they're set up to do."

If the video had been created by any other refugee advocacy or charity organization — one that did not have countries like the U.S. or the U.K. in its governing body — perhaps they could have asked viewers to take action on something more targeted. Colin Delany, a 20-year veteran of digital political communications and the founder and editor of , makes a suggestion.

"They could have asked people to put pressure on their own governments to support the refugee crisis," he says. "You need the major governments to push the U.N. to do something."

Copyright 2021 NPR. To see more, visit https://www.npr.org.