The golden beauty: brain response to classical and renaissance sculptures

Abstract

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 1. Example of canonical and modified stimuli.

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.

Figure 2. Brain activation of canonical and modified sculptures vs. rest.

The analysis was carried out by averaging activity across the three experimental conditions (observation, aesthetic judgment, proportion judgment). Group-averaged statistical parametric maps are rendered onto the MNI brain template (P-corrected<0.05).

Figure 3. Brain activation in the contrast canonical vs. modified stimuli.

a, Main effect of canonical vs. modified sculptures across conditions rendered onto the MNI brain template. b, Parasagittal and coronal view showing activations of the right insular region in the main effect. c, Activity profile of the right insula. For each condition (O, AJ, PJ) the signal plots show the difference between canonical (C) minus modified (M) sculptures in arbitrary units (a.u), +/− 10% confidence intervals (P-corrected<0.05).

Figure 4. Brain activations in the contrasts “judged-as-beautiful vs. judged-as-ugly” and “judged-as-ugly vs. judged-as-beautiful” stimuli.

a, Parasagittal, coronal and transaxial sections showing activation of the right amygdala in the interaction stimulus (beautiful vs. ugly)×condition (observation; aesthetic judgment; proportion judgment). b, Activity profile of the right amygdala. For each condition (O = observation, AJ = aesthetic judgment, PJ = proportion judgment) the signal plots show the difference between beautiful (B) minus ugly (U)-as judged sculptures in arbitrary units (a.u), +/− 10% confidence intervals. c, Statistical parametric maps rendered onto the MNI brain template showing activity within left somatomotor cortex in the contrast of ugly vs. beautiful stimuli averaged across the three conditions. d, Activity profile (ugly-beautiful) of the left motor cortex. For each condition (O, AJ, PJ) the signal plots show the difference between ugly (U) minus beautiful (B)-as judged sculptures in arbitrary units (a.u), +/− 10% confidence intervals (P-corrected<0.05).