Two prerecorded productions of the “What's this?” question were presented to Grade 2, 4, and 6 children and to adults over a series of trials in a referential communication task. One production contained emphatic stress on the word “this” and the other production contained equal stress on both words. For each question presentation the experimenter selected a colored picture of an object from a deck that was the match to one of two picture choices in view of the subjects. The students guessed on successive presentations whether a different picture (new topic collaboration) or the same picture (old topic collaboration) had been selected based on the presence or absence of emphatic stress in the questions. No feedback was given to the students throughout the experimental procedure. Use of intonation as a marker for topic collaboration appeared by Grade 4, which is in support of other similar research.