This paper reports an investigation of the effects of two plans on children's listener behavior in a referential communication setting. The design systematically varied the presence and absence of instructions about a plan to engage in comparison activities (comparison plan), and instructions about a plan to request more information if the speaker's message was ambiguous (action plan). Subjects were 94 elementary school children who played the role of listeners. The speaker was an adult confederate who produced messages of varying informational adequacy. Results show that on an immediate test, children receiving the action plan asked more questions when the messages were ambiguous and made more correct referent choices than other subjects. These effects persisted on a test administered two weeks later. No significant effect of the comparison plan was observed on either the immediate or the delayed test. Overall, the results suggest that knowing when and how to request additional information is an important listener skill. (Author)