Are children naturally inclined toward kindness, and does that tendency change as they grow older?

Those questions were at the heart of a recent study that explored how children make social and moral decisions. Researchers observed children's choices across a series of games, comparing those who had to respond quickly with those given time to reflect.

Their goal was to understand how intuitive and deliberate decision-making develops in children aged three to ten.

Candy games and moral choices

One of the experiments involved four candies and three boxes marked with drawings representing other children. Participants were told that the other children were playing from a different school and would never know who made which decisions.

The children could:

Keep all four candies.
Share two candies and keep two.
Contribute all four candies.

The candies placed in a communal bowl would be doubled and divided equally among all four children.

To test the role of instinct versus reflection, researchers added a time element. Some participants had only 10 seconds to decide, while others were instructed to pause and think carefully before choosing.

The study, led by Francesco Margoni of the University of Stavanger and Francesco Nava of the London School of Economics, involved 537 Italian children between the ages of three and ten.

The youngest children who were required to decide quickly tended to act more generously, share more, lie less and accept unfair outcomes more readily than those encouraged to deliberate.

Competing theories about kindness

One longstanding theory suggests children are born with a natural tendency toward prosocial behaviour. Another argues that cooperation is learned through experience in families and social environments where helping others is beneficial.

If either explanation is correct, researchers expected young children to act kindly before engaging in extensive reasoning.

Although the team initially hoped to distinguish between those explanations, they ultimately concluded that their study design could not do so. Instead, the research focused on comparing fast, intuitive decisions with decisions made after reflection.

A series of social experiments

Each participant made 19 decisions across five different tasks.

In one game, children could voluntarily give candies to another child who would never know who donated them and could not repay the favour.

Another task involved accepting or rejecting an offer made by a partner. Rejecting the offer meant neither child received any reward.

A separate honesty game rewarded lying. Children secretly drew a card assigning them to either a green or yellow group. Telling the truth favoured the other participant, while lying increased their own reward.

Researchers also adapted the classic trolley dilemma for children. In one version, participants could redirect a runaway ball from five children toward a single child. In another, they could stop the ball only by pushing a child off a bridge.

Across all age groups, children were far more willing to redirect the ball than to sacrifice a child directly.

After the experiments, researchers informed participants that the other "players" were fictional and sent every child home with 20 candies.

Younger children show more intuitive kindness

Among three-year-olds, children who made rapid decisions scored higher on an overall measure of kindness that combined generosity, cooperation, honesty and willingness to accept unequal outcomes without retaliation.

By ages nine and ten, the differences between children who rushed and those who reflected had largely disappeared.

Interestingly, the change occurred mostly among the children who were encouraged to think before acting. Their kindness increased steadily with age, while the behaviour of children making quick decisions remained relatively stable.

One exception involved generosity toward a single recipient. In that task, children gave similar amounts regardless of whether they were rushed or allowed to deliberate.

Honesty changed with age

The largest differences between the two groups appeared in the honesty task.

Three-year-olds under time pressure were more likely to tell the truth. By age nine, however, both groups showed similar honesty levels.

As children grew older, those who deliberated became increasingly truthful, while those making quick decisions became somewhat less so.

Researchers also found that older children were generally more cooperative, more likely to reject unfair offers and more willing to redirect harm in the trolley-style scenarios.

Children's expectations of others also mattered. Those who anticipated greater cooperation from their partners tended to behave more generously themselves.

Important limitations

The researchers emphasised that the study examined only two specific situations: being rushed and being required to wait. It did not measure how children naturally decide when left entirely to their own pace.

All participants came from kindergartens and primary schools in Milan, northern Italy, between autumn 2023 and spring 2024. The researchers noted that regional differences in trust and social behaviour mean the findings may not apply universally.

Although a small number of children failed comprehension checks and were excluded from the final analysis, additional tests produced similar results even when the youngest participants were removed.

What happens during adolescence?

The researchers now plan to compare social decision-making across children, teenagers and adults.

Their interest stems from earlier work conducted in 2023 using a similar candy-sharing game with adolescents. Unlike the youngest children, teenagers became more self-interested when forced to make decisions quickly.

The findings suggest that somewhere between late childhood and adolescence, instinctive generosity may gradually give way to more self-focused instincts. Exactly when and how that transition occurs remains an open question.

The full study is published in Nature Human Behaviour.

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