Hierarchical planning abilities in children with specific language impairments.

The present study examined Cromer's (1983) claim that children with language impairments have a hierarchical planning deficit that affects language as well as performance on complex construction tasks. Subjects were 30 boys (ages 5-7 years), 15 with specific language impairments (SLI) and 15 with normally developing language. Children were asked to build four hierarchical structures: a block construction, a puzzle construction, a simple straw construction, and a complex straw construction. Children who failed to complete the complex straw construction were taught how to construct the model using a sequential strategy. The two groups tended to perform comparably on the block and complex straw construction, the easiest and hardest of the four constructions. The two groups performed least comparably on the puzzle, simple straw construction, and the training task. On the basis of these findings and recent work by Greenfield (1991), we concluded that it is time to reject the notion that a central hierarchical planning mechanism underlies language and non-language structures that contain hierarchical components. The possible exception is early in development before language and manual actions become more autonomous and modular in nature.