Sessions were videotaped for coding. One coder coded all sessions, while a second coder, who was not aware of the hypo theses of the study, coded a random sample of 20% of the data. Cohen’s was calculated for each maternal and child behavior: = .82 for maternal pretense, = .84 for maternalimitation, = .90 for maternal verbalizations, = .81 for child pretense, and = .86 for child imitation.