This series of four experiments on children's causal sequences was directed at: (1) extending Brown's research on temporal ordering to causal relationships portrayed in picture sequences; (2) investigating the developmental progression of skills involved in understanding and remembering sequences; and (3) examining the development of reversible thinking about causal sequences. Subjects were preschool, kindergarten and second grade children. All studies employed the same six sets of pictures. Each set contained eight pictures, a four-item causal sequence and four distractors. In general data suggest that there is a developmental progression in children's ability to operate with causal sequences: initially children can rearrange elements of a sequence; subsequently they can select and construct sequence components from a distracting array; and finally they can develop reversible operations in reconstruction of causal order. (MS)