Connectedness and the integration of parts with relations in shape perception.

Seven experiments investigated whether part connectedness would facilitate the perception of spatial relations among object parts. Experiments 1-4 showed that objects composed of connected parts are easier to distinguish from distractors in rapid serial visual presentation sequences than objects composed of separated parts and that this effect cannot be attributed to the presence of local features in the connected images. Experiments 5 and 6 revealed that image-based connectedness is neither necessary nor sufficient for the connectedness effect, and Experiment 7 showed that the connectedness effect is not a simple feature conjunction effect (i.e., it does not hold in a shape-color conjunction search task). These findings are consistent with the claim, central to the structural description theories, that the visual system not only decomposes objects into parts but also explicitly integrates those parts with their spatial relations.