This paper attempts to describe how sharing behavior develops. Subjects were pairs of children aged 4 to 15. The experimental situation follows the pattern of a rich sharing with a poor, that is, subjects do not possess the same amount at the beginning of the experiment. Three stages emerge:

  • — Up to 6–7 years the subjects do not compare the different sets (initial belongings, set to be shared) and proceed often by alternating actions (give and take).

  • — From 6–7 to 11–12 years they even out their final belongings (what they possess after sharing). Initial belongings and objects to be shared are considered in the same way.

  • — From 11–12 years on, there is a distinction between initial belongings and the set that is to be shared, based on the assumption that they are dealing with two different types of property.