Perception of order within disorder: 1. Visual ranking of random textures

摘要

A computer algorithm was developed to control the separate probabilities of various line lengths, or spatial frequencies, in unidimensionally random homogeneous visual textures of 50% density. For three reference frequencies, 5.2 cycles/degree, 1.05 and 0.52, the mathematical randomness of the patterns was compared to the perceptual randomness, using standard Stevensian ranking methods,† and the rank orders dc, in general, agree. However, visual sensitivity to the changes in statistical order decreases as a negative function, inversely proportional to the amount of statistical order that is present. Further, the overall finess of the ordering is complexly related to the field characteristics of the patterns and to whether free eye-scan is or is not allowed. We conclude that sensory randomness is in itself a fully organized holistic quality of perceptual experience, quite like brightness or hue, and that it can be fruitfully studied entirely in its own right.