Theory-of- mind-related abilities present a long development characterized by both vertical and horizontal décalages. A vertical type of décalage can be seen in children’s abilities to take into account, on a practical level, others’ intentional and mental states and use internal state terms to talk about them before they are able to succeed, at the dominant representational level of functioning, in false belief tasks. Several horizontal décalages can also be observed. It is only after success in FB tasks that children can talk about the mental states of characters in fictional stories. Moreover, ToM-related and other inferential elements are expressed earlier and more frequently in conversationally-constructed than in monologically-produced narratives. This paper examines in particular this type of horizontal décalage by comparing the types of explanations produced by eighty 6- and 7-year-old French-speaking children during a short conversational intervention (SCI) focused on the causes of the story events to those expressed in monological narratives, about the same wordless picture story, produced immediately after or before the SCI. The results confirm that children expressed more ToM- related and other inferential elements during the SCI than in the two monologically-produced narratives. However, the comparison between explanations produced during the SCI and in the immediately following monological narrative also reveals complex relations among understanding, knowing and expressing this knowledge. The reasons and the significance of the horizontal décalages found in the study are discussed.