Three experiments involving 345 children aged 5-6, 7-8, and 12-13 were performed to investigate the development of children's motives to help. Two experimental paradigms were developed to determine children's motives for helping behavior in a specific behavioral context. In the first paradigm, situations were created in which children had the opportunity to help. Each situation consisted of specific conditions for the performance of the helping act which reflected the motive to help. The situations were arranged in a regressive order; the child who did not help in the situation reflecting an advanced motive (e.g. altruistic), had the opportunity to do so in another situation which reflected a less advanced motive (e.g. to gain social reward). In the second paradigm, the situations were also structured in such a way that the condition of each situation reflected the motives as to why the child helped, but each child was placed only in one experimental situation. The first two experiments were performed using the first paradigm and the third one was performed using the second paradigm. The results of all three experiments indicate that the quality of the helping behavior changes with age; the older the children, the more they helped under both altruistic and normative conditions. These results support the contention that helping behavior develops sequentially. (Author/MP)