They used imaging technology called magnetoencephalography to look at the brain activity of 20 volunteers while looking at pretty paintings and ugly pictures of cities and found clear sex differences when the test subjects saw images they described as beautiful.

Women use more of the whole brain when appreciating a nice piece of art, while men use mostly the right side, Francisco Ayala of the University of California, Irvine and colleagues in Spain found.

The differences are likely linked to known differences in the way male and female brains process spatial information, and probably are unique to humans, Ayala and colleagues reported in the Proceedings of the National Academy of Sciences.

"The differences between the decorative objects found in Neanderthal and modern human sites support that idea of a 'modern brain' capable of appreciating beauty and its uses in different ways," they wrote.

Most explanations of why men and women process this information differently focus on the use of the brain to navigate spatially, they said.

"Perhaps women make use of both global and local features in making their judgments, whereas men only rely on global features."