Although work on ‘conservation accidents’ furthered study of the cognitive processes in Piagetian conservation tasks, there has been little attempt to use children's meta‐cognitive awareness as access to such processes. The present study sought (a) to replicate effects on number conservation of variation in transformation conditions and (b) to investigate children's processing of such tasks by means of their commentaries on silent video‐replays of their performances.Two separate groups of 64 children aged 5–7 years participated in two similar experiments, each comprising four transformation conditions involving a human experimenter or a toy fox. Neither between‐ nor within‐subject data showed any evidence of transformation condition effects upon conservation in either experiment. Children generally denied that the counters had really been moved by the fox and overwhelmingly asserted the necessity of the experimenter's presence. Theories concerning the effect of repeating the equivalence question, the role of toy animal interference and the influence of meta‐cognitive awareness in conservation were further contradicted by the failure of performance to relate to any aspect of the video‐replay commentaries gathered in Expt 2, including reported correctness of children's pre‐transformation judgement, their belief in the agency of the toy animal, and their construal of the purpose of the task. Memory lapses before and during the video commentary confirm the usefulness of this procedure as well as the need for caution in interpreting what it yields. The possible role and implications of experimenter effects in this area of research ar