Abstract
Children's ability to modify their drawing procedures changes in their first decade. Young children make size/shape changes and end-of-sequence insertions/deletions of drawing elements. Older children also make middle-of-sequence insertions/deletions and position/orientation changes in drawing elements. Why do modifications occur in this order? We argue that older children's modifications require processing ternary relations, which according to a relational complexity theory, is beyond the working memory capacity of young children.