Conservation without Conversation Revisited: A replication and elaboration of the Wheldall-Poborca findings on the nonverbal assessment of conservation of liquid quantity

A series of experiments by Wheldall and Poborca (1980) have demonstrated that more young children can conserve liquid volume when tested using a novel, nonverbal paradigm than when tested by conventional verbal assessment procedures. The present experiment attempted to replicate their findings and simultaneously assess the effects of two modifications to their original procedure. The results showed that the two modifications to the Wheldall and Poborca procedure—(i) inviting subjects to transform the liquid quantities themselves, instead of merely observing the experimenter do so and (ii) using an extended elaborated form of response training—did not significantly increase the number of children able to conserve liquid volume. However, the original Wheldall and Poborca findings were replicated, showing that some children are likely to be falsely classified as non-conservers if assessed using traditional verbal assessment methods.