From a recent Yahoo Labs report on aesthetics via Annie Sneed at Fast Company:
"The majority of people surveyed for the project also disliked abstract art, and favored curvy lines over sharp, jagged lines—both inclinations likely rooted in how the brain works. Our preference for curvy lines is supported by almost a century of psychological studies, and scientists have found it’s rooted in an evolutionary bias as well. Research has found that when people look at a sharp object in an MRI scanner, it activates a region of the brain (called the amygdala) that responds to danger, whereas curved objects don’t elicit this mental reaction. "Sharp objects in our past were associated with danger," Vartanian says. "This association has stayed with us, even though the environment we live in today is quite different."
"And as for abstract art: Well, it’s not hard to figure out why many people don’t like it. An abstract painting is highly conceptual, which means it takes a lot more energy to understand, whereas representational art has a storyline that the viewer can immediately follow. Similar to the photo filters, we typically prefer images that are easier to process. Vartanian notes that this bias doesn’t apply to people trained in visual arts—they tend to like abstract art much more. And there’s a lot of data showing that people with expertise in visual arts perceive paintings very differently overall than someone untrained, so their aesthetic preferences probably differ from the average person in general."