Washington: Kids as young as three years old know the rules of sharing but don't follow them until they are at least seven, according to a new study. The study published in journal PLOS ONE found that children understand sharing norms early, but follow the rules only from age 7 onward. "People who spend time with young children will know that they often favour themselves when sharing, but surprisingly they endorse equal sharing not just by other people but also in their own case," the authors wrote. "In our research, we were able to rule out a number of explanations for this early gap between word and deed," they said. When the US researchers gave 3-8-year-olds stickers they valued and asked them about sharing, children of all ages readily asserted that they themselves should share equally, and others should as well. However, when given the chance to actually share, children failed to follow the norms they endorsed until the ages of 7-8, reported researchers Craig E Smith from the University of Michigan, Peter R Blake from Boston University and Paul L Harris from Harvard University. The study concluded that though younger children know the norm of equal sharing, the importance they attach to it increases with age.