Uniform connectedness and grouping in the perceptual organization of hierarchical patterns.

The principle of uniform connectedness (S. E. Palmer & I. Rock, 1994) states that connected regions of uniform visual properties correspond to the entry-level units of visual stimuli. The implications of this principle for the perceptual organization of hierarchical patterns were investigated in 3 experiments. Primed matching and visual search were used to examine the microgenesis of organization for patterns that vary in number and relative size of their elements. Results for the few-element patterns showed an initial representation of elements with a weaker representation of global configuration. Grouping of elements into global configuration consolidated with time and involved focused attention. The entry-level units of many-element patterns were global configuration and texture. Individuation of elements occurred later and involved focused attention. These findings are discussed with reference to processes underlying perceptual organization.