Fehr, E., Bernhard, H., & Rockenbach, B. (2008). Egalitarianism in young children. Nature, 454(7208), 1079–1083. http://doi.org/10.1038/nature07155

This is a classic and crucial study. The authors use an extremely simple experimental design (inspired in previous work with non-human primates) to test the hypothesis of a parallel development of children’s egalitarianism and parochialism. Children between 3 and 8 years of age are presented three situations:

• Prosocial: either take one candy and assign one candy to another child, or take one candy and assign none to another child ((1,1) vs. (1,0).
• Envy: either take one candy and assign one candy to another child, or take one candy and assign two candies to another child ((1,1) vs. (1,2).
• Costly sharing: either take one candy and assign one candy to another child, or take two candies and assign none to another child ((1,1) vs. (2,0).

The study shows that children, as they grow, aim at reducing the inequality between themselves and their partner, regardless of whether the inequality is to their advantage or disadvantage.

The authors found that children at age 3–4 show little willingness to share resources (as tested by the sharing situation) but a non-negligible percentage of the children is willing to make choices that benefit the recipient if it is not costly (in the envy and prosocial situations). After this age, other-regarding preferences develop, which take the form of inequality aversion instead of a preference for increasing the partner’s or the joint payoff.

Thus, across the three situations, egalitarian choices increase with age. “If we pool the children’s choices in all three games, the percentage of children who preferred the egalitarian allocation in all three games increases from 4% at age 3–4 to 30% at age 7–8.” Also, “(…) the share of subjects who maximize the partner’s payoff by choosing both (1,1) in the prosocial game and (1,2) in the envy game decreases sharply from 43% at age 3–4 to 16% at age 7–8.” Egalitarianism rises as generosity declines.

This emphasis on equality (or inequality aversion) seems to be uniquely human; no animal shows a comparable behavioral pattern.

In addition, children (especially boys) seem to show an in-group bias. For example, in the envy game, boys tend to do egalitarian distributions (1,1) rather than generous distributions (1,2) more with the outgroup than with the ingroup. The effects of parochialism are also apparent in the other situations: In the prosocial game, the children remove inequality that favors themselves more often if the partner is an ingroup member. In the sharing game, egalitarian choices slightly decrease over time if the partner is an outgroup member, whereas sharing with ingroup members strongly increases with age

The conclusion is not only that egalitarianism and parochialism are important forces driving children’s judgments, but also that is that a utilitarian ethics seems absent from children’s minds. In other words, children do not try to maximize the total sum of benefits for everybody. That is why, in the “envy” situation, children (at least after 5 or 6 years of age) tend to prefer (1,1) over (1,2); that is, egalitarianism trumps maximization of benefits. Utilitarianism is not a factor in children’s reasoning. Equality aversion and parochialism grow between 3 and 8 years of age and explain children’s responses.

Comparing this paper with other studies, it is interesting to note that equality is said to appear at 5, or 6, or 7 or 8 years of age depending on the study, the methodology used and the way the results are interpreted (e.g., Rochat says that children at 5 are already steady defenders of strict equality and that they even can adopt an ethical stance, when they are willing to sacrifice their own resources to punish an agent that is not observing equality).

In addition, it is relevant to understand young children’s (3 and 4 year-olds) apparent discrepant or erratic behavior (sometimes they are generous, at other times they are selfish). In a previous study I claimed that the reason for this is that those children “don’t frame their relationships in terms of strict-reciprocity (tit for tat) contracts. It should be no surprise that their behavior in economic games and fairness experiments is consistent with a culture of associative reciprocity and the gift economy, which predominate in the context of familial institutions and peer relationships at this age. Preschoolers might appear as non-strategic from the point of view of economists who identify rationality with calculating the best means to achieve a desired end-result (individual profit, equality, etc.), but they are actually well adapted to their real social context. (…)  The apparently selfish tendencies of 3-year-olds moderate themselves as children mature, so that between five and seven years of age (depending on the specific study) children start demanding fairness and rejecting inequality. In certain cases, they even embrace an ethical stance and engage in costly punishment. This emerging mindset is in harmony with the strict reciprocity embedded in experiences such as bartering with peers or dealing with money and prices, which gain prominence in children’s daily life as they grow up. In the culture of adults, barter and monetary transactions are considered fair when both parties receive an equivalent value. Similarly, fair distributions between partners with the same merit are expected to be 50/50. This kind of institutional context comes to dominate children’s interactions and provides them with a new sense of fairness.”