What is schema anomalies?

Schema anomalies is a concept in personal epistemology: When reality repeatedly contradicts your schema the schema needs updating.

Example: A product manager notices three separate user complaints about the same "edge case" in one week. Rather than patching each individually, she recognizes the pattern as a signal that her mental model of user behavior is wrong — the edge case is actually the main case for a segment she had not modeled.

This concept is part of Phase 16 (Schema Evolution) in the How to Think curriculum, which builds the epistemic infrastructure for schema evolution.