Two children, Anne and Carla, have worked together to make a cake and they have to split it between them. Anne says that she’s the bigger cake aficionado and deserves the lion’s share. But Carla demands the bigger slice since she did most of the cooking. A nosy third party, Brenda, argues that the only fair call would be for the two girls to split the cake equally. Which is the right path?

There’s no obvious right answer and different people will probably side with different viewpoints. Dilemmas like this have been the subject of much philosophical debate, and they’re a common part of everyday life. How do you allocate pay rises between your staff? How should the UK’s new government split its budget among its various departments?

According to Norwegian scientist Ingvild Almås, our attitudes to such questions change during our childhood and adolescence, as we start changing our opinions on what counts as ‘fair’. Children tend to shun any form of inequality – they’d agree with Brenda. But as they enter the turmoil of adolescence, they become more meritocratic and are happier to divide wealth according to individual achievements, as Carla suggested. As their teens draw to a close, they (like Anne) pay greater heed to efficiency, making choices of maximum benefit to the group.

Almås studied these shifts by working with 486 Norwegian children between the 5^th and 13^th grade (ages 10-11 and 18-19 respectively). She asked them to play a version of a money-sharing task called the dictator game. To begin with, the kids had 45 minutes to spend between two websites. In the first, they could earn points by spotting specific numbers among a digit-filled screen. The other was full of videos, cartoons and games but bereft of point-scoring opportunities. Afterwards, their points were traded for actual cash at either a high or low exchange rate. Their total earnings reflected their own achievements and efforts, as well as a smattering of luck.

In the next phase, the kids were paired with others from the same grade. Each one knew how long their partner had spent earning points, how well they had done, and what their exchange rate was. The pair’s winnings were pooled and one of them – the dictator – had to choose how to split the total. Overall, the children were remarkably fair. On average, dictators from all the age groups gave their partner around 45% of the total pot. However, a closer look within each age group revealed a striking difference.

The majority of 5^th-graders (around two-thirds) were egalitarians, who shared their money equally no matter the circumstance. But this philosophy became less popular with age and by the 9^th grade, just a quarter of the children held this attitude. By contrast, meritocrats, who gave more money to the child who had earned the most points, became more common with age. They accounted for just 5% of 5^th-graders but made up around 40% of 11^th and 13^th-graders. A third group – the libertarians, who were generally happy with any division of wealth, even based on luck – made up a third or so of the group at all ages.

So adolescents are happier to accept inequalities as long as they’re based on merit. What about efficiency? To study that, Almås modified the game so that the children’s points were only exchanged for cash after the dictator’s choice. They would get one krone (the Norwegian currency) for each point they kept, but their partner’s share would be multiplied by either 1, 2, 3 or 4 times. In the latter scenarios, the pair would gain the most total money if the dictator gave away all the points.

The 5^th and 7^th graders didn’t particularly care. Even when their partner’s points would be quadrupled, they only gave away slightly more points. However, the late adolescents were more swayed and parted with significantly more points as their partner’s multiplier increased. On the whole, efficiency factored into the kids’ decisions a few years after they began to give more weight to merit. And unlike merit, which influenced both boys and girls equally, boys placed greater importance upon efficiency than girls did.

Why the changes? Almås says that it’s easy to be completely egalitarian or libertarian; based on these philosophies, you can divide wealth with relative ease. It’s far more complicated to consider merit and efficiency, where you’d need to filter relevant information and make calculations. These are things that get easier as children mature.

However, this hypothesis can’t account for the fact that fewer adolescents stick to the egalitarian attitude of childhood. An alternative explanation is that as they grow up, children become increasingly exposed to competitive areas where they are rewarded based on their achievements, be they in the classroom or in a sporting ground.

Like many studies of this sort, the volunteers all come from a WEIRD country (Western, Educated, Industrialised, Rich and Democratic), which makes them psychologically, well, weird from a global perspective. Do the same experiments in other parts of the world and you might well find different results.

Reference: Science http://dx.doi.org/10.1126/science.1187300

Photo by Knut Egil Wang

More on fairness:

• Clean smells promote generosity and fair play; dark rooms and sunglasses promote deceit and selfishness
• Genes affect our likelihood to punish unfair play
• Dogs frown on unfair rewards
• The right side of fair play
• Children learn to share by age 7-8
• Selfless monkeys find personal reward in helping others