From Visual Perception to Aesthetic Appeal: Brain Responses to Aesthetically Appealing Natural Landscape Movies

Abstract

During aesthetically appealing visual experiences, visual content provides a basis for computation of affectively tinged representations of aesthetic value. How this happens in the brain is largely unexplored. Using engaging video clips of natural landscapes, we tested whether cortical regions that respond to perceptual aspects of an environment (e.g., spatial layout, object content and motion) were directly modulated by rated aesthetic appeal. Twenty-four participants watched a series of videos of natural landscapes while being scanned using functional magnetic resonance imaging (fMRI) and reported both continuous ratings of enjoyment (during the videos) and overall aesthetic judgments (after each video). Although landscape videos engaged a greater expanse of high-level visual cortex compared to that observed for images of landscapes, independently localized category-selective visual regions (e.g., scene-selective parahippocampal place area and motion-selective hMT+) were not significantly modulated by aesthetic appeal. Rather, a whole-brain analysis revealed modulations by aesthetic appeal in ventral (collateral sulcus) and lateral (middle occipital sulcus, posterior middle temporal gyrus) clusters that were adjacent to scene and motion selective regions. These findings suggest that aesthetic appeal per se is not represented in well-characterized feature- and category-selective regions of visual cortex. Rather, we propose that the observed activations reflect a local transformation from a feature-based visual representation to a representation of "elemental affect," computed through information-processing mechanisms that detect deviations from an observer's expectations. Furthermore, we found modulation by aesthetic appeal in subcortical reward structures but not in regions of the default-mode network (DMN) nor orbitofrontal cortex, and only weak evidence for associated changes in functional connectivity. In contrast to other visual aesthetic domains, aesthetically appealing interactions with natural landscapes may rely more heavily on comparisons between ongoing stimulation and well-formed representations of the natural world, and less on top-down processes for resolving ambiguities or assessing self-relevance.

Keywords: aesthetic appeal; elemental affect; fMRI; landscape movies; naturalistic stimuli; neuroaesthetics; scene preference; value.

FIGURE 1

A continuous rating paradigm for assessing individual aesthetic enjoyment of landscape videos. (A) Schematic description of one experimental trial measuring continuous aesthetic responses to dynamically changing visual experiences. Participants viewed 30 s movie clips of landscapes while making continuous ratings of their moment-to-moment enjoyment. This was followed by an overall rating indicating the intensity of the aesthetic experience from the whole movie. Both responses were given using a rotary dial. (B) The histogram of overall ratings collapsed across all participants shows that most ratings were above the ‘indifference’ point (marked here as 0). (C) However, the distribution of overall ratings as illustrated with boxplots suggests marked differences across people in terms of their overall aesthetic ratings (Diamond is the mean, center line is the median, bottom and top edges of the box indicate the 25th and 75th percentiles. Whiskers extend to the most extreme data points and black circles indicate individual outliers). (D) Measure of agreement across participants (“mean-minus-one” correlation, see Materials and Methods) for overall and continuous ratings. Each circle represents the MM1 value for one participant and the gray dashed lines connect the MM1 values computed with overall and continuous ratings for the same participant. Diamonds are mean MM1 values across participants; error bars are 95% confidence intervals. (E) Continuous rating traces given by each participant for one movie clip (with the median MM1c value). In general, movie clips were rated differently by different participants, in terms of their overall mean liking and variability over time.

FIGURE 2

Strength of BOLD activation vs. baseline and effect of aesthetic appeal in visual, default-mode and reward networks. (A) Nineteen a priori regions of interest (ROIs) from three networks were identified and mean signal from each ROI was extracted for each participant. (B) Activations in each ROI for viewing landscape movies (vs. baseline). All visual ROIs were strongly engaged by landscape movies, with pericalcarine, LO, and OPA showing the strongest activation. *Indicates greater and ^†indicates lesser activation compared to a resting baseline (C) Beta values from a univariate activation analysis in a priori visual ROIs did not reveal significant differences across 4 different levels of aesthetic appeal. In B, C, boxplots display the median (center line), the 25th and 75th percentiles (box edges) and extrema (whiskers). Filled circles represent scores for each participant and points outside the reach of the whiskers are individual outliers; N = 24.

FIGURE 3

Brain regions modulated by aesthetic appreciation of landscape movies. Significant clusters of activations from a whole-brain beta series GLM analysis are shown for group contrasts of 4 vs. 1 (white outlines) and 4 vs. 321 (solid red: cortical, red outline: subcortical) levels of aesthetic appeal. N = 24. Black outlines show the scene-selective regions as found by the functional localizer task. PPA, parahippocampal place area; OPA, occipital place area; NAc, Nucleus Accumbens.

FIGURE 4

Comparison of stimulus-induced and appeal-related activations for both movies and still images of natural landscapes. Significant clusters from stimulus vs. baseline and aesthetic appeal contrasts (4 vs. 321) from two experiments were rendered on Freesurfer’s fsaverage cortical surface. Solid warm colors illustrate movie vs. baseline contrast (yellow) and effect of high appeal movies (4 vs. 321, red). Outlined cold colors illustrate still images vs. baseline contrast (teal) and effect of high appeal images (4 vs. 321, purple) obtained with static natural landscape images from Vessel et al. (2019). Top: inflated surfaces showing a ventral view of right (RH) and left (LH) hemispheres, and lateral and medial views of the left hemisphere. Bottom: flattened left hemisphere. Movie N = 24, Image N = 16.

FIGURE 5

Predicting trial-wise functional connectivity estimates between a priori ROIs from visual, reward and DMN networks. FC scores were computed between each pair of a priori ROIs, separately for each movie stimulus, and modeled as a function of overall aesthetic ratings using both linear and quadratic regressors. Heat maps show t-scores from group level one-sample t-tests, conducted with the t-scores from the regressions for each edge. For the linear effect of aesthetic appeal (lower half), FC modulations were observed mainly between nucleus accumbens (NAc) and sensory ROIs and NAc and OFC ROIs (see text). For the quadratic effect (upper half) FC modulations were found between reward and sensory ROIs, between reward and DMN ROIs and within reward ROIs. N = 24. No scores were significant at q < 0.05 corrected for multiple-comparisons (false-discovery rate). One edge, (pallidum:aMPFC quadratic) was less than p < 0.001 (uncorrected).