Disturbing vision
Place: Large Lecture Room
Affiliation: Department of Psychology, University of Essex., UK
Observers show consistency in the images they judge to be uncomfortable. The discomfort can be predicted from the statistics of the image, and this applies to images ranging from photographs of everyday scenes to geometric arrays, coloured or in motion. Images are generally rated as uncomfortable to view if (1) the luminance contrast energy has a power spectrum that departs from 1/f, or (2) the CIE UCS chromaticities are widely separated, or (3) the contours flicker at about 20Hz. For the same variety of images, those that are uncomfortable result in a large cortical haemodynamic response, measured either with fMRI or near infrared spectroscopy. Individual differences in the size of the haemodynamic response appear to reflect a cortical hyperexcitability, possibly due to a failure of GABAergic inhibition, common in migraine, and providing clues as to the mechanisms of discomfort. The biological utility of the discomfort can be understood not only as homeostatic, but also as an evolutionary adaptation because images of venomous animals possess the properties of uncomfortable images and are indeed uncomfortable to view. There are far-reaching implications for the design of our visual environment because much of our environment has characteristics that are uncomfortable.
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