In Detroit a contemporary-art museum is completing a monument to an influential artist that will not feature his work but will instead provide food, haircuts, education programs and other social services to the general public.

In New York an art organization that commissions public installations has been dispatching a journalist to politically precarious places around the world where she enlists artists and activists — often one and the same — to write for a Web site that can read more like a policy journal than an art portal.

And in St. Louis an art institution known primarily for its monumental Richard Serra sculpture is turning itself into a hub of social activism, recently organizing a town-hall meeting where 350 people crowded in to talk about de facto segregation, one of the city’s most intractable problems.

If none of these projects sound much like art — or the art you are used to seeing in museums — that is precisely the point. As the commercial art world in America rides a boom unlike any it has ever experienced, another kind of art world growing rapidly in its shadows is beginning to assert itself. And art institutions around the country are grappling with how to bring it within museum walls and make the case that it can be appreciated along with paintings, sculpture and other more tangible works.

Known primarily as social practice, its practitioners freely blur the lines among object making, performance, political activism, community organizing, environmentalism and investigative journalism, creating a deeply participatory art that often flourishes outside the gallery and museum system. And in so doing, they push an old question — “Why is it art?” — as close to the breaking point as contemporary art ever has.

Leading museums have largely ignored it. But many smaller art institutions see it as a new frontier for a movement whose roots stretch back to the 1960s but has picked up fervor through Occupy Wall Street and the rise of social activism among young artists.

“Say what you will, this stuff is happening, and you might want to put your head in the sand and say, ‘I wish it was 40 years ago and it was different and art was more straightforward,’ but it’s not,” said Nato Thompson, the chief curator of Creative Time, a New York nonprofit that is known mostly for temporary public art installations but has been delving deeply into the movement. The interview could be consulted in the edition of The New York Time on March 24^th 2013.

Works can be as wildly varied as a community development project in Houston that provides both artists’ studios and low-income housing, summer camps and workshops for teenagers run by an artist collective near Los Angeles or a program in San Francisco founded by artists and financed by the city that helps turn yards, vacant lots and rooftops into organic gardens.

Art of this kind has thrived for decades outside the United States, mostly in Europe and South America, but has recently caught fire with a new generation of American artists in what is partly a reaction to the art market’s distorting power, fueled by a concentration of international wealth. Many artists, however, say the motivation is much broader: to make a difference in the world that is more than aesthetic.

“The boundary lines about how art is being made are becoming much blurrier,” said Laura Raicovich, who was hired last year by Creative Time as its director of global initiatives and to run a Web site called Creative Time Reports.

Social-practice programs are popping up in academia and seem to thrive in the interdisciplinary world of the campus. (The first dedicated master of fine arts program in the field was founded in 2005 at the California College of the Arts in San Francisco, and today there are more than half a dozen.) But for art institutions the problems are trickier: How can you present art that is rarely conceived with a museum or exhibition in mind, for example community projects, often run by collaboratives, that might go on for years, inviting participation more than traditional art appreciation?

At the Pulitzer Foundation for the Arts, a private institution founded by the collector and philanthropist Emily Rauh Pulitzer that opened in St. Louis in 2001, the staff for many years
included two full-time social workers who helped former prison inmates and homeless veterans as part of the curatorial program. And in December the foundation, responding to a 2012 BBC report about racial and economic disparities in St. Louis, held a town-hall meeting on the issue. The goal was to open a dialogue with people who live near the institution, which sits near a stark north-south divide between mostly white and African-American neighborhoods.

“We hoped maybe 100 people would show up, and more than 350 did,” said Kristina Van Dyke, the foundation’s director, who collaborated with the Missouri History Museum in organizing the event.

“The question became: Could we effect social change through art, plain and simple?” she said, adding that the foundation is now exploring ways to orient its programming toward design projects that would help the poor, for example. “To me art is elastic. It can respond to many different demands made on it. At the same time I have to say that I don’t believe all institutions have to do these kinds of things, or should.”

Some in the art world feel that all institutions (and artists) should resist the urge completely. Maureen Mullarkey, a New York painter, wrote on her blog, Studio Matters, that such work only confirmed her belief “that art is increasingly not about art at all.” Instead, she argued, it is “fast becoming a variant of community organizing by soi-disant promoters of their own notions of the common good.”