Testing the “Boundaries” of boundary extension: Anticipatory scene representation across development and disorder

Recent studies have suggested that Boundary Extension (BE), a scene construction error, may be linked to the function of the hippocampus. In this study, we tested BE in two groups with variations in hippocampal development and disorder: a typically developing sample ranging from preschool to adolescence and individuals with Down syndrome. We assessed BE across three different test modalities: drawing, visual recognition, and a 3D scene boundary reconstruction task. Despite confirmed fluctuations in memory function measured through a neuropsychological assessment, the results showed consistent BE in all groups across test modalities, confirming the near universal nature of BE. These results indicate that BE is an essential function driven by a complex set of processes, that occur even in the face of delayed memory development and hippocampal dysfunction in special populations.