Developmental Psychology, in press Fitting objects into holes: On the development of spatial cognition skills

14to 26-month-old infants’ understanding of the spatial relationships between objects and apertures was studied in an object manipulation task. The task was to insert objects with various cross-sections (circular, square, rectangular, elliptic, and triangular) into fitting apertures. A successful solution requires the infant to mentally rotate the object to be fitted into the aperture and use that information to plan the action. On half the trials the object was presented standing up and on the other half it was lying down. The results showed that infants solved the problem consistently from 22 months and that a successful solution was associated with appropriate pre-adjustments before the hand arrived with the block to the aperture. No sex differences were found.