The game works like this: the puppet (with the aid of an adult puppeteer) and a three-year-old participant gather their hauls of little buckets. Then the child/puppet team is rewarded with stickers - one for each coin they have collected.At this point the child has to decide how to share his or her prized stickers with their puppet partner.
This simple game revealed that, by the age of just three, children choose to reward their peers based on merit. The children gave the puppet more stickers if it had “worked harder” - gathering more coins.
Patricia Kanngiesser from the University of Bristol led the study, which was published in the journal PLoS One. She said she was amazed by the result.
“We were very surprised to find this sophisticated sharing behaviour already present in three-year-olds,” said Ms Kanngiesser.
“Previous research has found that children don’t really begin to share according to merit until they are six years of age and older.”
Using puppets allowed the experimenters to carry out a controlled experiment whilst still revealing exactly how the children would behave towards peers in a real world situation.
For even a young, pre-educated child to understand basic notions of fairness does strongly suggest that it’s natural to us. Even more fascinating is the evidence that shows that even our fellow primates have similar compunctions:
In recent years there has been increased scientific interest in whether non-human primates are able to understand the concept of fair play.
As well as gaining an understanding of the complexities of animal behaviour, these studies are trying to unpick its evolutionary origins.
The first of these was published in Nature in 2003. Sarah Brosnan, currently at Georgia State University, found that capuchin monkeys reacted dramatically to being treated unfairly.
Dr Brosnan trained wild monkeys to work with human handlers on a simple task; the monkey would hand over a piece of rock and, in return, receive a food reward.
In the experiment, two monkeys sat side by side. The handlers either gave both monkeys an identical reward (a slice of cucumber) or gave just one of the monkeys the much preferred reward of a grape for completing exactly the same task.
As it was reported at the time by National Geographic: “Capuchins who witnessed unfair treatment and failed to benefit from it often refused to conduct future exchanges with human researchers, would not eat the cucumbers they received for their labours, and in some cases, hurled food rewards at human researchers.”
Since then, several groups have tried to test fairness in our closer and apparently more intelligent cousins - the great apes.
But, Dr Shultz said, overall, “non-human primates, apes included, are not very good at solving fairness problems”.
In other words, complex moral and ethical behavior remains uniquely human, as far as we can tell. But the fact that our closest relatives have some rudimentary concept of it implies that we built upon pre-existing foundations for fairness and justice.