Egalitarianism in young children

A very interesting article from Nature. It showed:

1) "At age 3–4, the overwhelming majority of children behave selfishly, whereas most children at age 7–8 prefer resource allocations that remove advantageous or disadvantageous inequality".

2) "The egalitarian choice is roughly 15%–20% more likely in the prosocial game if the partner is an ingroup member" and "the difference between sharing in the ingroup and outgroup conditions strongly increases with age. Thus, the children's altruism and parochialism emerges simultaneously between the ages of 3 and 8 and is associated with a very strong ingroup bias at age 7–8"

Also "boys show much stronger parochial tendencies than girls do"

3) "On average, children without siblings were 28% more likely to share than children with siblings"--interesting, you would think the opposite is true--"With increasing age, however, the difference between children with and without siblings decreases slightly".

"Among the children with siblings, we found that—regardless of age—the youngest children in a family were 17% less willing to share than children with younger siblings"--that makes intuitive sense.

The bottom line: as children grow up they developed "parochial altruism"--less selfish but only to their own people. Make sense, almost like another sign of "bounded rationality".