ABSTRACT
Is the transition from immature to more mature forms of psychological function one of quantitative change or qualitative change? This classic question in developmental theory can be asked about any developmental trend. Here, we ask about the trend from more holistic to more differentiated comparisons of objects. In particular, we ask the qualitative-versus-qualitative question about the well documented findings that, in perceptual classification tasks, young children classify objects by their overall similarity, whereas older children classify by identities on single dimensions. Does this trend reflect principally a change in the frequency, magnitude, or amplitude of a psychological variable or process? Or does the trend reflect a qualitative change—a change in the structure or organization of underlying processes?
