Children's categorical representation of oblique orientation

20 7-yr.-old children were given a memory task in which they were asked to compare successively presented oblique lines. The lines varied in respect to (1) their position within a square display and (2) their relation to the diagonal axis of the display. Children's performance suggests a categorical spatial representation system in which stimuli are encoded in terms of position and axis features. In comparing the orientation of two oblique lines, children match these coded categorical features (e.g., on axis vs off axis) and respond by the simple response rule: if a match say "same," if a mismatch say "different," so, children's recognition of oblique lines is often in error.