Abstract
Maternal and child mental state language is associated with improved socioemotional and cognitive child development. This study examined if introducing a story stem (a narrative playing out socioemotional conflicts) in a play situation facilitated maternal and child mental state language compared to a free-play (baseline) situation, and if mothers and children with low baseline mental state language profited more from the story stem situation. Participants were 101 four-year-old children and their mothers. Maternal and child mental state language correlated and providing the story stem increased both maternal and child mental state language. Providing a story stem increased mental state language more for mothers and children groups with lowest mental state language at baseline compared to a high mental state language group. The results indicate a validation of the use of story stems to increase maternal and child mental state language within a typical population.