Schissler, D. R. (1969). Analysis of pictures by subjective ratings and by eye fixations. Journal of General Psychology, 81, 83-94.

Subjects used various scaling techniques to rate small areas of a picture in terms of relative informativeness. Both category and magnitude scales showed high reliability across subjects and methods. The resultant scale of informativeness was correlated with eye fixations on the picture for areas of various sizes. Correlations increased with the size of the area employed. Several possible explanations of this effect were discussed. Correlations differed for areas of different sizes when the figure and background were analyzed separately, which suggested that the size of the perceptual field changes with variations in detail within a picture.