for a transitivity-of-length concept. The transitive Ss in each of these groups participated in a transitivity task and a simple line-judgment task, both of which involved a simulated group-conformity situation. Their performance was compared with that of a control group to assess the effects of conformity on the stability of the transitivity concept across age. The results indicated that conformity decreased as age increased. Some evidence for the increasing stability of the transitivity concept with increasing age was considered; however, strong support for this relation was not indicated by the results. The effects of task-irrelevant cues on performance in Piagetian tasks was discussed. According to Piaget (e.g., 1951) the child's intellectual resources become greatly enriched owing to the emergence of concrete operations. These are regarded as cognitive structures, and their existence is inferred from certain changes in the child's characteristic mode of behavior when confronted with certain types of problems. These behavioral changes, which indicate entry into the period of concrete operations, are thought by Piaget to occur around the age of 7. As one manifestation of the entry into this period, the child acquires the ability to make transitive inferences. Most of the literature on this topic has been concerned with transitivity of length. A concept of concrete transitivity is said to be present when, after one observes that object A is longer