When a child's existing idea fails and the child revises the idea itself, Piaget calls this:

1. Piaget's two adaptation processes are assimilation and accommodation. 2. Accommodation is the revision or modification of an existing concept in the light of new experience. 3. Revising the idea itself (not just fitting new data into it) is accommodation. **Why not the others:** Assimilation keeps the idea unchanged; centration and seriation are features of particular stages, not adaptation processes. _Source: Seifert and Sutton, Educational Psychology, 2nd ed. (2009, CC BY 3.0), Ch 2, section "Psychological constructivism: the independent investigator", p. 34_