Young kids often yell, "That's not fair!" Here is a question. What makes something fair? Let us look at rules, turns, rewards, ways to split things and ways to decide.

Part of being fair is following the rules. Simple board games and card games help kids practice. They practice following rules and taking turns.

Kids learn to share and take turns by playing with other kids. Taking turns is one way to share. Two kids can share a toy. Each one gets an equal turn. A timer can show when a turn is over.

Sharing takes time to learn. Toddlers under 3 are often reluctant to share. They do not yet understand what sharing means. Kids often get better at it around age seven or eight. A child can also keep a few special things just for themselves. A child does not have to share everything.

Kids know about fairness very early. Babies seem to notice unfair sharing. They look longer at unfair outcomes. Even very young children understand what is fair, and they often protest, "That's not fair!" Studies in many places found that children dislike getting less than another child. Capuchin monkeys in experiments reacted badly to getting a less-favored reward when a partner got a better one.

Knowing and doing are not always the same. Young children know they should be fair. But they often still keep more for themselves. Children will sometimes give up their own reward to keep things even with another child.

What about rewards? Young children understand that someone who worked harder may deserve more reward. Yet young children often prefer to hand out rewards equally, even when one person worked harder. They also expect people who do equal work to share the reward equally.

"I cut, you choose" is an old, standard way for two people to split a cake. The one who cuts makes two pieces they think are equal. The other person picks the slice they like best. So neither person envies the other. Cake is not the same all the way through. So two pieces of the same size can be worth different amounts to different people.

Sports have fair rules too. In soccer and in the NFL, the referee flips a coin before the game to decide who gets the first choice. Fair play is usually thought of as following the rules. It includes respecting the referee.

Voting is one way to decide. Here is how it works. In a majority vote, the choice with the most votes decides the outcome.

Words to know

• reluctant: not wanting to
• equally: the same
• referee: game official
• majority: most of them
• rules: what to follow

The short version

Part of being fair is following the rules. Even very young children understand what is fair, and babies seem to notice unfair sharing. Kids often get better at sharing around age seven or eight. In "I cut, you choose," the other person picks the slice they like best, so neither person envies the other.

Quick facts

• Part of being fair is following the rules.
• Babies seem to notice unfair sharing: they look longer at unfair outcomes.
• Children often get better at sharing around age seven or eight.
• In "I cut, you choose," the other person picks the slice they like best, so neither person envies the other.
• In a majority vote, the choice with the most votes decides the outcome.