Abstract: The importance of transitive inferences is not dispute to psychologists.Since Piaget indicated this,many developmental psychologists have studied the transitive ability in children.Some investigators made the point that children have difficulties in transitive inferences not because their ability in reasoning,but their low memory span.Young children have a fairly low memory span,so it is hard for them to remember the premises of inferences.So,it is important to design an experiment that can not only examine children's ability of transitive inferences,but also eliminate the need for the memory load.In this study,we designed two tasks in which children could see the premises at the time that they were asked the inferential question,one for length transitivity and the other for weight transitivity.Our aim was to discover whether young children could work out the transitivity problems(A>B,B>C:A?C). 32 children aged from 5 to 6 participated in this study.We used computer to present the problems and let children chose the correct answer from two pictures.The results were as follows:(1)Children aged 6-year-olds did better than children aged 5-year-olds,this age effect was significant;(2)Children's performance was similar in different tasks.(3) The direction of premises had no significant effect on children's performance.These results of this study indicated that children's ability to do transitive inferences developed fairly rapidly from 5 to 6,and children aged 6-year-olds were able to make transitive inferences about length and weight.

Key words: transitive inference, the concrete operational stage, direction of premises