Abstract
We investigated the spontaneous perception of structure in random dot patterns (RDPs) and the role of the grouping principles of proximity, collinearity, and good-continuation. In three experiments observers reported the perceived organization in RDPs by either circling the groups they perceived or by clicking on the dots that appeared to belong to the same groups. We analyzed these reported organizations were analyzed within-subject and between-subject consistency, and they were used as the foundation for a quantitative model. This model uses graph-theoretic techniques to determine the neighborhoods of dots in the random dot patterns. Within these neighborhoods it computes the strengths of grouping by proximity, collinearity and good-continuation. In a computer simulation the model performed multiple trials with the experimental stimuli and, in a stochastic process, predicted grouping frequencies. Our data were accurately accounted for by a model based on grouping by proximity and good-continuation that computed neighborhoods in a global fashion. In a fourth experiment we tested this model in a new context and investigated the time-course of perceptual organization in RDPs. The predictions of the model captured the observers' performance in this experiment; display duration did not affect the responses. We interpret the results of these experiments and the model-fitting as evidence that the perceptual organization of RDPs is an early, automatic, and global process.
This is work that MvdB did for his PhD dissertation. Supported by NEI and NIDCD