Recently, a distinction has been drawn between conventional false memories, which misrepresent specific facts, and deep distortions, which misrepresent relations that connect facts. We report the first study of adult developmental trends in deep distortions, using a paradigm in which people make conjoint recognition judgments about incompatible facts (e.g., Was Einstein born in Austria, Germany, or Switzerland?). As conventional false memories increase over the adult lifespan, it is natural to expect that deep distortions will do likewise. Surprisingly, however, the modal explanation of adult increases in false memory predicts that deep distortions will be developmentally invariant. We tested that prediction in two experiments that measured three deep distortions (violations of the logical laws of additivity, countable additivity, and universal event) in memory for real-world incompatibility relations (e.g., size of planets, geographical location of companies, people in historical events). In Experiment 1, robust violations of all three laws were detected in younger adults (