A closer look at children's metacognitive skills: The case of the distinctiveness heuristic.

•We document the developmental course of distinctiveness effects in childhood.•In Experiment 1, pictures and words were displayed in two separate lists.•In Experiment 2, the two types of stimuli were presented within the same list.•A reduction in false recognition rate was found when a pure-list design was used.•No reduction was found when items were presented using a mixed-list design.