The Walters Art Museum might not be the largest research laboratory in the world. Nor is it the most prestigious, since its curatorial staff includes exactly zero Nobel Prize-winning scientists.

But surely no other facility in which a pioneering neurological hypothesis is currently being tested can boast such elaborate wall decor.

Museum director Gary Vikan says that a gallery is the perfect setting for "Beauty and the Brain," which opened this weekend and which is equal parts art exhibit and science experiment. The pioneering collaboration between the Walters and the Johns Hopkins University aims to find out whether humans are hard-wired to find some shapes and forms inherently more pleasing than others.

Vikan and Charles "Ed" Connor, director of the university's Mind/Brain Institute, know of no other instance in which a public arts institution has volunteered to gather data for a research laboratory.

"Since my college days, I've been interested in understanding how people recognize and appreciate beauty," Vikan says. "When neuroscience began poking into economics and religion and other areas of human endeavor, I thought we could be a leader as a museum by partnering with researchers and tackling these age-old issues."

Unfortunately, the Walters has a strict prohibition against rats, so the study will be conducted on the two-legged test subjects known as museum visitors.

Here's how it works:

Gallery guests pick up a clipboard and put on a pair of 3-D glasses. They examine a series of 25 small drawings based on abstract sculptures by renowned 20th-century artist Jean Arp. The drawings, reminiscent of the old Rorschach "inkblot" tests, differ from one another subtly.

In one row, the protrusions might gradually become less curved and more pointed. In the next row, the limblike extensions might shrink in relation to the torso.

Participants mark which images they like best, and which least. They then go on to the next series of 25 drawings.

Vikan says that researchers deliberately selected abstract forms instead of statues of people or animals because modern art puts the building blocks of visual experience - color, shape and line - front and center instead of allowing them to retreat into the background.

The experiment is using variations of sculptures instead of paintings, he says, because our brains translate even flat images on canvas into three-dimensional forms.

"We look at things in 3-D," he says. "It's almost impossible not to. Using a sculpture that's already 3-D just simplifies the process."

The exhibit at the Walters complements a project under way at the Mind/Brain Institute. The museum will generate data from a large number of people evaluating a small number of shapes. The sister study on the Hopkins campus does just the opposite.

But as market researchers have discovered, figuring out which artworks (or products) consumers favor is a complicated matter. It isn't always enough to simply ask them, partly because people's heads can interfere with their guts.

So the second phase of the experiment will explore whether images that appear to generate strong positive or negative feelings correspond to a measurable burst of neurological commotion. A smaller group of test subjects will be shown a series of pictures while hooked up to a machine. Researchers will track the volunteers' blood-flow levels to determine which parts of their brains are being stirred up, and when.

"People are willing to spend millions of dollars to buy sculptures that have no earthly purpose other than stimulating the pleasure systems in the brain," Connor says. "It's pretty amazing."

He and Vikan hope to learn if there are certain shapes that trigger universal aesthetic responses. The notion that there is a "Platonic ideal," or invisible archetype for every physical object, has been kicking around for about 25 centuries, ever since the Greek philosopher went about haranguing his students about shadows projected on cave walls.

More recently, the art critic Clive Bell coined the term "significant forms" to talk about the way people perceive visual beauty. Are humans innately drawn to smooth curves? Do we reflexively flinch away from stilettos? And if so, why?

"Artists are instinctive neuroscientists," Vikan says. "They're always looking for new ways to stimulate perceptual mechanisms. When we're involved in looking at art, the whole brain is fully engaged. It's one of the most sophisticated things we can do."

When scientists say that a reaction is common to all of mankind and is independent of history, time and cultural constraints, they're saying it is inherited. And if, for example, an attraction toward or avoidance of spiky shapes is passed down among the generations, researchers conclude that the predilection carried with it an important survival advantage.

"But we're a long way from knowing what those advantages might be," Connor says. "One theory among many is that spiky things may drive the visual brain too hard. It might be like shouting."

The collaboration between Hopkins and the Walters is similar to other research being conducted on the neurological basis of music. While the so-called "Mozart effect" - the theory that listening to the composer's sonatas can make kids smarter - has been debunked in recent years, there is some indication that there may be an inborn, worldwide preference for certain qualities of music, such as consonance over dissonance, according to Daniel Levitin, a neuroscientist at McGill University in Montreal, for harmony over tension.

If Plato, Clive Bell and Ed Connor turn out to be right, such a discovery could raise a ruckus in the art world.

If it is discovered that human brains are hard-wired to respond to certain shapes, it could be just a small step to conclude that art based on these ideals is good, and art that deviates from them is bad. And artists have never liked being told how to paint, sculpt or compose songs.

If there are in fact "significant forms," it might raise the issue of how to account for artwork that is unpopular but important. It would ask whether the purpose of art is to entertain, or to help people grow. Babies might not like dissonant music, but many adults do.

Vikan and Connor acknowledge that their research could be controversial, though any discoveries that might eventually be made are years, if not decades, into the future. And they say that scientists - and for that matter, artists - should be free to ferret out knowledge without worrying in advance about its political implications.

As Connor puts it: "Nothing is more fascinating than trying to figure out how a handful of electrical impulses give rise to what we think and feel and create. Some day, we hope to be able to show people, 'This is your brain on art.' "

If you go "Beauty and the Brain" runs through April 11 at the Walters Art Museum, 600 N. Charles St. Hours: 10 a.m. to 5 p.m. Wednesdays through Sundays. Free. Call 410-547-9000 or go to thewalters.org.