Young children who abandon error behaviourally still have to free themselves mentally: a retrospective test for inhibition in intuitive physics.

When preschoolers overcome persistent error, subsequent patterns of correct choices may identify how the error had been overcome. Children who no longer misrepresented a ball rolling down a bent tube as though it could only fall vertically, were asked sometimes to approach and sometimes to avoid where the ball landed. All children showed requisite task-switching flexibility. The pattern of 4-year-olds' correct choices among different places showed unnecessary avoidance of any place that would previously have tempted them into a vertical-approach error, 5-year-olds rebounded into a reversal, and 7-year-olds were flexible. The data attest to an inhibition mechanism, ruling out competing possibilities.