Abstract
The colors of paintings and natural scenes are closely related (Montagner et al, 2016, JOSA A). We hypothesized that aesthetic preference for colors might be related to their perceived naturalness and that both judgments might rely on similar brain mechanisms. We asked participants (N=19) to rate images of natural scenes on aesthetic preference and naturalness in a psychophysical experiment and while in the fMRI. The degree of naturalness and beauty was manipulated by rotating the color gamut of the images in CIELAB. The images were presented either in their original form or spatially manipulated using a modified version of the 'eidolon factory' (Koenderink et al, 2017, JoV) to remove their semantic content, but preserving the original color statistics. In the behavioral experiment participants performed pairwise comparisons on images of the same scene but with different gamut angles. We obtained individual scaling curves for naturalness and preference as a function of the angle of rotation, using maximum likelihood difference scaling. The naturalness and preference scaling curves were largely similar and their maxima were close to the original image for all conditions and scenes (on average within 20°), suggesting that perception of naturalness and preference are indeed closely related. In the fMRI experiment, the same images were presented one by one in an event-related paradigm and the same participants rated them again for naturalness and preference. We subsequently used the individual scaling curves as parametric regressors to test for brain regions where activity modulated with perceived level of naturalness or preference. Results suggest that unscrambled scenes with natural colors activate the Parahippocampal Place Area more than unscrambled scenes with very unnatural colors. Interestingly, there was also a weak modulation of naturalness close to a region in orbital frontal cortex that has previously been reported to be modulated by preference.
Meeting abstract presented at VSS 2018