An analogous knowledge-lean task is the colorless liquid task originally used by Inhelder
and Piaget (1958). Kuhn and Phelps (1982) presented four diVerent Xasks of colorless
Xuid to fourth- and Wfth-graders. The researcher demonstrated that by adding several
drops of a Wfth Xuid, one particular combination of Xuids changed color. On subsequent
weekly sessions, the children’s task was to determine which Xuid or combinations of Xuids