Tested 8 groups (180 Ss) on measures of continuous and discontinuous quantity conservation. The 8 groups were trained and untrained Grade 2 conservers and Grade 5, Grade 7, young adult, middle-age adult, elderly, and institutionalized elderly Ss. All Ss who reached criterion on quantitative invariance judgments were then tested for resistance to conservation of quantity extinction. Both
... [Show full abstract] resistance judgments and explanations were found to develop in a curvilinear fashion, increasing with age until young adulthood and declining thereafter. (15 ref)