Jean Arp's 1959 sculpture "The Woman of Delos" is a symphony of rolling curves.
The figure is full-bodied and undulating. Despite the material used to make it — plaster — it conveys an impression of forgiving softness. There's a concave shape on the upper left, where the woman's head curves into her shoulder, and a convex shape on the lower right, where her arm is connected to her torso.
Though Arp may not have been consciously aware of all that he was doing, "The Woman of Delos" is almost perfectly designed to stimulate certain pleasurable mechanisms in the human brain.
Research presented Thursday by a Johns Hopkins University researcher may help explain why some abstract, three-dimensional artworks, such as Arp's "Woman," elicit a visceral response from the majority of people gazing upon them, while other pieces leave viewers cold.
"No one knows for certain why some things are aesthetic and some are not," Charles "Ed" Connor, a professor in the university's department of neuroscience, said Thursday at a conference on "The Science of the Arts" organized by Hopkins' Brain Science Institute. "More follow-up, more analysis of the data, needs to be done. But we now have a working hypothesis."
Connor and his team think that primates may be hard-wired to respond to ample forms possessing a certain configuration of concave and convex shapes. Skilled sculptors and architects may instinctively exploit these involuntary responses to create profound artistic experiences.
Connor's presentation was just part of the two-day session that examined such knotty questions as how the brain's representation of space informs architectural design, the neural mechanisms behind musical improvisation, and why the same internal circuits that evolved to recognize food and family members fire up when people enjoy a sunset or a painting.
"An instinctual knowledge and innate understanding of beauty is one of the most defining characteristics of what it means to be human," Jack Griffin, director of the Brain Science Institute, told conference attendees."But the connection between art and brain functions has long been a mystery."
For more than a year, Connor's team tested about 3,000 volunteers at the Brain Science Institute and visitors taking in an exhibit at the Walters Art Museum called "Beauty and the Brain."
Test subjects donned 3-D glasses and were shown several sets of abstract slides. Each slide contained 25 small drawings based on Arp sculptures that differed from one another in small ways.
For instance, as a viewer's eyes moved from left to right, protuberances roughly corresponding to the sculpture's "head" and "arms" might get progressively smaller and less distinct. Or, the image as a whole might grow skinnier and more elongated.
The test subjects were asked to identify which image on each slide they liked the most, and which the least.
It's unusual to conduct a science experiment inside a museum, and Walters director Gary Vikan said that his customers had a varied response to the slides.
"About 20 percent loved it, 20 percent absolutely hated it, and 60 percent were bewildered by it," he said.
Despite the subjects' attitudes, the results, Connor said, were remarkably consistent, showing a preference for fullness and curves — not only with other human test subjects, but across species.
The research team showed a group of monkeys drawings similar to those scrutinized by the human subjects, and monitored the animals' brain activity. The images that generated the most neural commotion among the primates turned out to be comparable to the humans' favorite images.
"There are lots of cells in the nervous system for identifying surface curvature," Connor says. "When you take away volume, you take away surface curves. Maybe lower volume forms don't provide the rich stimulus that these neural systems respond to."
Still, that prompts the question: What is it about curves that is so important for survival that we are programmed genetically to seek them out?
There is, of course, an obvious correlation between curves and nourishment, between the shape of a cow's udders, or an apple, or a tomato, and the message that food is at hand. But, the case for curves is more complicated than that.
"The curved parts of an object convey information that helps us recognize it," Connor said.
A study by University of Southern California neuroscientist Irving Biederman has shown that when a panel of volunteers examines a series of drawings of objects from which all the curved lines have been removed, they are baffled. But, when the process is reversed — when the angles and planes are taken away, but the curves remain intact — most people have no problem identifying the objects the shapes represent.
Connor emphasized that his data are tentative and provisional at best. He would be the first to acknowledge that there may well be other neurological pathways in the brain that respond to different artistic attributes.
"It is very, very speculative," he said. "There are a lot of ways that our hypothesis could be picked apart and proven wrong."
The next step, he said, will be to put a small group of volunteers into a functional magnetic resonance imaging machine and chart the actual neurological activity that occurs when a person, and not a monkey, looks at a work of art.
Several of the researchers and artists attending "The Science of the Arts" appeared intrigued by Connor's experiment.
After the panel, William Stoehr, a Denver-based painter known for his realistic and moving portraits smeared with red, said that the findings seem to replicate the painter's own, more intuitive investigations.
"All of my life, I've been in search of the perfect line," Stoehr said. "I haven't found it yet, but far and away the one that works best for me is a curve."
Semir Zeki, a professor of neuroesthetics at University College of London, praised Connor's team for tackling "questions about the connection between art and brain science that go back two millennia and that are well worth addressing."
For his part, Vikan, the Walters' director, hopes his institution will be involved in future experiments. He's considering mounting a show at the Walters that would explore the sense of touch. He envisages an exhibit that would explore whether some textures are inherently more aesthetically pleasing than others.
"I hope these collaborations that we've set up will continue long after I'm gone," he said.