Infants Believe In Fairness, Until Resources Are Scarce


Stephen Luntz

Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.

Freelance Writer

monkey puppets

Very young children expect puppet monkeys to divide cookies fairly when there are enough to go around, but to favor other monkeys over giraffes when there are not enough cookies for everyone. Oleg1824/Shutterstock

Infants just 18 months old expect people will treat others fairly, as monkeys do. Unfortunately, at the same age they also expect people to favor those like them over those who are different. These two ideas come in conflict, and which one triumphs depends on whether there is enough to go around. Basing our ethics on the views of infants may be unwise, but it's certainly worth knowing where we come from as we try to work out the best way to allocate resources.

Getting very young children to allocate resources is hard, so Stanford University's Dr Lin Bian tested expectations instead. She had 18-month-old infants and 30-month-old toddlers watch puppet shows where cookies were allocated. It's long been established that very young children will stare longer at things that surprise them than those that align with expectations. Therefore, when allocations didn't match expectations, the children's surprise could be measured in the time they spent watching.


In Proceedings of the National Academy of Sciences, Bian tested responses when witnessing divisions between two puppets, made by a third puppet. If a monkey puppet was distributing three cookies between themselves, another monkey, and a giraffe, the children showed signs of puzzlement if the allocator showed species bias by giving two cookies to the other monkey and none to the giraffe. The same was true in the reverse case when a giraffe made the distribution.

However, when there were only two cookies between the three puppets, expectations reversed. The children expected the monkey to keep one cookie for itself and give the other to the other monkey. The divider monkey sacrificing their own cookie for the giraffe induced surprise.

There was even more astonishment if a puppet favored the other species over its kin.

The work builds on previous studies where children as young as 10 months stared in surprise when windfalls were divided unevenly between equally deserving individuals. Similarly, at 15-16 months children have been shown to choose someone who has divided goods fairly over someone who has given more to one person than others.


The fact that both fairness and in-group favoritism appear to be innate, or learned very early, is an important observation. Arguably, many elections come down to one side arguing for a fairer deal for all, while the other wants to give more to members of the portion of the population with which they identify (be it a tribe, race, or class) even if this is often disguised. Not everyone's views on these matters will be fixed by the age of two and a half, but Bian's work implies people will be more inclined to support even sharing when they think there is enough to go around.


  • tag
  • fairness bias,

  • in-group bias,

  • infant expectations,

  • ethical conflicts