Counterintuitive age increases have been reported for the Deese-Roediger-McDermott (DRM) false memory illusion. The current theoretical explanation of this effect assumes that it is due to age increases in spontaneous interconnection of DRM list words' meanings. To test this explanation, 11-year-olds and young adults studied DRM lists under conditions that (a) encouraged them to form such meaning-based connections or (b) discouraged them from doing so. In line with the explanation, the usual developmental increase in false memory disappeared in the first condition but was preserved in the second condition. Also in line with the explanation, conjoint recognition analyses revealed that encouraging participants to form meaning connections increased their reliance on gist-based similarity judgments.