Two boys fishing with nets

An experiment found that some children spontaneously adopt techniques to manage a limited resource.

Human behaviour

Six-year-olds can cooperate to protect common assets

Children use adult-like tactics to tackle ‘tragedy of the commons’ puzzle.

Children just six years old can devise strategies to share a limited resource equitably.

Rebecca Koomen and Esther Herrmann at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, designed a tank that filled slowly with water. Water flowed out of the tank through two taps, each of which led to a series of bottles. At each tap, a six-year-old controlled the flow of water into the bottles.

If the two children waited patiently for water to accumulate in the tank, both could collect water in their bottles — and so earn sweets. But if either child took too much water at one time, both lost their access to the water in the tank.

Some children spontaneously developed cooperative strategies that allowed both members of a pair to receive similar rewards without jeopardizing the common resource. They agreed to wait for the tank’s water level to rise, and they distracted one another to pass the time. These tactics resemble those used by adults facing similar challenges, the authors say.