Perceptual supports for one-to-one correspondence in the conservation of number

This study compared provoked and spontaneous one-to-one correspondence along with two tasks having more perceptual support for correspondence. These four levels of correspondence appeared in a conservation of number condition and two conservation-related conditions (a partially static array or a static array). There were two sets of stimuli (toy animals or corks) in each condition. In opposition to Piaget's predictions, the four levels of correspondence did not differ in difficulty for kindergarteners. There was a strong order effect (p<.001) in the direction of increasing conservation over the eight trials. There was some evidence that the standard conservation condition was easier than the other two conditions. Implications for Piaget's theory are discussed.