Spatial categorization has a long history in the research of infant cognition and perception. Many conclusions are drawn from the approach wherein infants are habituated to examples of a spatial category X and then display an attention recovery (i.e., dishabituation) to a contrasting category Y. However, the distinction infants make between X and Y does not warrant a distinction between X and another category Z. Here we examine the boundaries of infants' spatial categorization by contrasting the spatial category "containment" with "support" and "occlusion." Eight-month-olds were habituated to 3 exemplars of containment and were tested with novel containment versus support events, or with novel containment versus occlusion events. The infants looked significantly longer at the support than at the containment events, but they looked about equally at the occlusion and containment events. The results suggest that 8-month-olds treated exemplars of containment as belonging to the same category, generalized this category to novel examples, and distinguished it from support but not from occlusion (this last distinction emerged by 11 months). Thus, spatial categorization in the 1st year, like several other domains of cognition, may be tied to specific contrasts. Whether infants form a broad or narrow spatial category depends on the contrasting category.