The relative effectiveness of positive and negative adult preference statements in controlling children's behavior was studied. Results indicated that the adult's antecedent negative comments exerted greater control over the children than did the positive comments. (ST)

This study was designed to determine the extent to which (speech) motor timing control, as defined by a statistical model, improves in consistency with age and the degree to which peripheral feedback is used by children to maintain this consistency. Clinical applications and possible genetic implications are discussed. (Author/ED)