Spatial aspects of spontaneous object grouping by young chimpanzees (Pan troglodytes)

I report spontaneous spatial object grouping in five chimpanzees (Pan troglodytes) ranging from 1 to 4 years of age, recorded subjects' spontaneous interactions with groups of objects, noting the spatial relations in the groupings and the constructive processes that the subjects adopted. Though one subject developed vertical stacks, none of them realized horizontal alignments or spatial correspondences between groups. All subjects showed consistent trends in their constructive processes toward manipulating objects in relation to the body: they increasingly manipulated objects globally, that is to say, they moved or held objects together with the same part of the body. They also increasingly placed objects on the body or in correspondence to their symmetrical body parts. The increasing importance assigned by chimpanzees to body-object relations over object-object relations contrasts with human developmental trends in the domain of manipulative space.