Despite what many grown-ups might think, toddlers have a marked sense of fairness. In a recent study published in Psychological Science, a journal of the Association for Psychological Science, 3-year-olds shared a small reward with their peer after they worked together to earn it, even in situations where it was easy for one child to keep all the spoils.

To learn how youngsters share, the researchers paired children to complete a task for a prize, like gummy bears or colorful stickers, piled on a board with wheels inside a transparent box. If only one child pulled on a rope, the board wouldn’t move, but if both pulled together, they could bring it close enough to reach the prize through windows in the box. Some boxes had only one window, so one child could easily grab the prize and keep it, but the toddlers nearly always shared the reward with their partner. Sometimes, if one child didn’t take their half of the spoils immediately, the other even pointed it out.

The insight for all of us: If we cooperate, everyone is better off.