One of the most debated issues in aesthetics is whether beauty may be defined by some objective parameters or whether it merely depends on subjective factors. The first perspective goes back to Plato's objectivist view of aesthetic perception, in which beauty is regarded as a property of an object that produces a pleasurable experience in any suitable viewer. This stance may be rephrased in biological terms by stating that human beings are endowed with species-specific mechanisms that resonate in response to certain parameters present in works of art. The alternative stance is that the viewers' evaluation of art is fully subjective. It is determined by experience and personal values
The above text begins a paper in PLoS ONE from Rizzolatti and colleagues, and addresses this issue. Here is their abstract and one figure from the paper.
Is there an objective, biological basis for the experience of beauty in art? Or is aesthetic experience entirely subjective? Using fMRI technique, we addressed this question by presenting viewers, naïve to art criticism, with images of masterpieces of Classical and Renaissance sculpture. Employing proportion as the independent variable, we produced two sets of stimuli: one composed of images of original sculptures; the other of a modified version of the same images. The stimuli were presented in three conditions: observation, aesthetic judgment, and proportion judgment. In the observation condition, the viewers were required to observe the images with the same mind-set as if they were in a museum. In the other two conditions they were required to give an aesthetic or proportion judgment on the same images. Two types of analyses were carried out: one which contrasted brain response to the canonical and the modified sculptures, and one which contrasted beautiful vs. ugly sculptures as judged by each volunteer. The most striking result was that the observation of original sculptures, relative to the modified ones, produced activation of the right insula as well as of some lateral and medial cortical areas (lateral occipital gyrus, precuneus and prefrontal areas). The activation of the insula was particularly strong during the observation condition. Most interestingly, when volunteers were required to give an overt aesthetic judgment, the images judged as beautiful selectively activated the right amygdala, relative to those judged as ugly. We conclude that, in observers naïve to art criticism, the sense of beauty is mediated by two non-mutually exclusive processes: one based on a joint activation of sets of cortical neurons, triggered by parameters intrinsic to the stimuli, and the insula (objective beauty); the other based on the activation of the amygdala, driven by one's own emotional experiences (subjective beauty).
Figure legend: The original image (Doryphoros by Polykleitos) is shown at the centre of the figure. This sculpture obeys to canonical proportion (golden ratio = 1∶1.618). Two modified versions of the same sculpture are presented on its left and right sides. The left image was modified by creating a short legs∶long trunk relation (ratio = 1∶0.74); the right image by creating the opposite relation pattern (ratio = 1∶0.36). All images were used in behavioral testing. The central image (judged-as-beautiful on 100%) and left one (judged-as-ugly on 64%) were employed in the fMRI study.