Modification of the frequency of descriptive adjectives in the speech of Head Start children through modeling without reinforcement.

Children enrolled in a Head Start program were instructed to describe the contents of each of four boxes of toys. After the subject's initial description (baseline), the experimenter (model) described the contents of three boxes of different toys in alternation with the subject's descriptions. For one group, the experimenter used descriptive adjectives in his descriptions. In a second group, the experimenter used no adjectives of any kind. A marked increase in the frequency of descriptive adjectives was observed during the first description after modeling in the first group. This increase was maintained in successive descriptions at approximately the frequency used by the experimenter. Frequency of descriptive adjectives remained at zero or decreased in the second group.