Days after two black men were arrested at a Starbucks store in Philadelphia, the company announced a drastic response.

At the end of May, Starbucks stores across the US will close en masse and 175,000 employees will undergo racial bias training, a programme developed by progressive equality organizations.

Starbucks is seen as one of the more progressive US employers and has been praised for the measure. But experts warn that real change will take much more than a one-off training session.

“Just doing training is not enough,” said Holly Hutchins, associate professor of human resource development at the University of Houston’s College of Technology. “Organizations tend to rush to the training option as a way to quickly window-dress issues, especially around gender or racial bias.”

Of all the options available for educating the workforce, Hutchins said diversity training “actually has the least impact”.

“People are feeling like they’re going to be strong-armed into changing their beliefs and perspectives about something, and it can often trigger even more stereotypes and backlash,” she said.

Rashon Nelson and Donte Robinson were arrested in Philadelphia on 12 April. The men, both 23, were sitting at a table waiting for a business meeting and had yet to order a drink. A manager called the police and Nelson and Robinson were handcuffed and led from the store.

In an interview with the Associated Press, Nelson and Robinson said they had feared for their lives. Video footage recorded by a customer went viral.

Heather McGhee, president of Demos, an equal rights thinktank, will develop the Starbucks training plan with the former US attorney general Eric Holder and representatives of the NAACP Legal Defense and Education fund, the Equal Justice Initiative and the Anti-Defamation League.

McGhee said she was not surprised by what happened to Nelson and Robinson.

“It called to mind some of my earliest memories as an African American of feeling unwelcome and being discriminated against in stores and restaurants and movie theaters,” McGhee said. “This is – more than most people who are not black know – a regular part of the considerations we have when moving through public and private spaces in America.”

McGhee said that while the closure of stores and the implementation of racial bias training was an eye-catching step, it would serve “really as an introduction”. It was important that Starbucks carried on the work, she said, including encouraging “interpersonal interactions” among employees of different races and backgrounds.

“It is very important that we take this opportunity to go as deep as we possibly can,” she said. “To review the policies and procedures, to have a longer-term engagement with Starbucks management about these issues on a deeper level.”

That means looking at specific rules employees were given, McGhee said, down to making it clear what the standards were for people waiting in stores and what the rules were regarding people using the bathroom. Nelson said he asked to use the bathroom and was refused before the Starbucks manager called the police.

Starbucks has a reputation as one of America’s better employers. The company offers free university tuition for the duration of an employee’s degree, in a partnership with Arizona State University. Those working 20 hours a week or more are eligible for health insurance.

Starbucks’ chief executive, Kevin Johnson, said after the incident the company was “committed to being part of the solution” regarding racial bias. McGhee said Starbucks’ response at least showed it was prepared to try to improve.

“I think it’s encouraging that because of the public pressure, because of the activists on the ground, and because of where Starbucks wants to be as a company, they took a higher road,” she said.

Joelle Emerson, chief executive of Paradigm, a company that works with businesses to improve inclusivity and equality, agreed that Starbucks needed to examine procedures employees were told to follow.

“You can’t train bias out of people,” she said. “I hope that in addition to training, Starbucks looks at making systemic and structural changes to address what’s fundamentally a systemic and structural problem stemming from our country’s history of racism.

“Processes and policies that guide employees’ actions are an important complement to training and can go a long way towards reducing the influence of bias.”

Hutchins said it would also be key for Starbucks to make sure teams that work together or go through training together come from a mix of backgrounds.

“Where you get a diverse array of individuals on a team you get individuals who have different perspectives,” she said.

That could help people understand issues that people of different races might face, said Hutchins, at the University of Houston. But to really effect change, any company needed to develop a range of measures – changing policies and procedures, as McGhee outlined; mentoring staff; and making sure that it was hiring a diverse staff.

“And all of that signals to the general employee that diversity is not just something you talk about,” Hutchins said. “It’s not something that just appears as a few words on our company webpage or in the annual report, but that it’s something that is an ongoing, lived-up-to value.”