Abstract
Images with spatial or chromatic properties that are uncharacteristic of typical visual environments tend to be rated as less comfortable to view (Fernandez and Wilkins Perception 2007; Land et al. VSS 2009). This effect could reflect how visual responses are normalized for the image statistics that are routinely encountered in natural viewing. Here we examine whether short term exposure to modified statistics alters judgments of visual discomfort, to assess whether perceptions of discomfort can be recalibrated for the observer's ambient environment, and whether this adjustment reflects renormalization of perceived image qualities through a process like adaptation. Images consisted of a dense collage of overlapping rectangles of different colors (Mondrian patterns) that could be varied in their spatial (e.g. blurred or sharpened) or spectral (e.g. mean color and color and luminance contrast) properties. In further conditions we also explore the effects of prior adaptation on discomfort ratings for images of art that have been shown to be uncomfortable because they include excessive energy at medium spatial frequencies. Observers initially adapted to a rapidly changing sequence of images with a common attribute that would normally appear comfortable (e.g. focused) or uncomfortable (e.g. blurred). They then used 7-point scales to rate both the perceived discomfort and the aesthetic quality of a succession of test images (e.g. ranging from blurred to sharpened) that were each shown interleaved with periods of readaptation. Separate measurements also directly evaluated changes in the adapting attribute (e.g. perceived focus). Adaptation strongly changes the appearance of the images, and we use the changes in the ratings to assess the extent to which perceptions of both discomfort and aesthetics are tied through this adaptation to the average characteristics of the visual environment.