Response to Gierut, Elbert, & Dinnsen (1987).

Further analysis of the data presented by Gierut et al. showed that some similar patterns of change for untreated sounds were characteristic of subjects in both groups. These similarities make the performances of the two groups less different than Gierut et al. indicated. The patterns of change observed in subjects from both groups may involve maturation, relationships among cognates, or some general effect of treatment. Furthermore, the present analysis supported the conclusion of Gierut et al. that the performance of subjects from the two groups did differ in some respects. However, these differences may be related to other factors not identified by Gierut et al.: (a) subject variables, or (b) the number of opportunities subjects had to make changes in cognates of targets and to make changes in cognates of untreated sounds that were associated with high pretreatment knowledge. As Gierut et al. were careful to point out, further studies of the effect of target choice on changes in the phonological system are needed. Future research should attempt to rule out the potentially confounding factors identified here.