Combined fMRI and eye-tracking evidence on the neural processing of visual ambiguity in photographic aesthetics

While visual ambiguity is known to play a central role in modern art, the neural correlates of its processing remain substantially unexplored in the case of aesthetic stimuli. To fill this gap, we combined eye-tracking and functional magnetic resonance imaging (fMRI) to investigate both visual exploration, and the associated brain activity and connectivity, when observing (WO) or evaluating (WE) either ambiguous (AMB+) or non-ambiguous (AMB-) artistic photographic stimuli. These manipulations highlighted more fixations (suggestive of higher loading on exploratory processes) when evaluating compared with observing, and stronger right fronto-parietal and occipito-temporal activity (possibly supporting the resolution of visual ambiguity through attentional reorienting to global vs. local aspects) when processing ambiguous compared with non-ambiguous stimuli. Task-by-stimulus type interaction analyses showed that evaluating ambiguous stimuli was specifically associated with stronger fixation-related activity in the left medial prefrontal cortex, as well as decreased connectivity from this region to its right-hemispheric homologue, possibly supporting in-depth visuospatial analyses of complex visual images. These findings pave the way for future studies addressing the role of visual ambiguity in aesthetic appreciation, as well as the factors that might ease vs. hamper its processing and resolution, and their neural correlates.