Thank you for visiting our web page with illustrative videos of several of our studies! You will find short descriptions of our studies with links to the original research articles. We hope you find them useful — let us know if you have questions!

Please be aware that these videos are exclusively for educational and research purposes. They can only be used with explicit permission from the authors and reference to the respective articles. If you are interested in using them in lectures or talks, please email us at

Helping in infants and chimpanzees

What are the origins of altruistic helping? We found that 18-month-old infants already help in a variety of situations in which an adult is struggling to complete a task — without being asked to help or being rewarded for their efforts. In addition, we found that chimpanzees show some of these basic helping behaviors as well, highlighting the deep roots of altruistic behavior.

Warneken & Tomasello (2006). Altruistic helping in human infants and young chimpanzees. Science.

Child helps with an out-of-reach object

Child helps by correcting a wrong result

Child helps with an obstacle

Child helps by correcting a wrong means

Chimpanzee helps with mould

Chimpanzee helps with a dropped lid (v1)

Chimpanzee helps with a sponge

Chimpanzee helps with a dropped lid (v2)

The origins of collaboration

In this study, we investigated whether children and chimpanzees are able to solve problems that require their collaboration with partners. In certain trials, the experimenter stopped participating in a joint activity, and we recorded whether children and chimpanzees would try to re-engage the partner to continue the collaboration or switch to individual problem solving instead. Both children and chimpanzees were able to coordinate with a partner, but only children tried to re-engage the partner during the interruptions.

Warneken, Chen, & Tomasello (2006). Cooperative activities in young children and chimpanzees. Child Development.

Child: Parallel roles & re-engagement

Child: Complementary roles & re-engagement

Chimpanzee: Behavioral coordination

Chimpanzee: Coordination & no re-engagement

Do rewards help or hinder helping?

In this study, we were interested in the effect of rewards on children’s helping. We found that children who received a toy for helping during a treatment phase were later less likely to help during our test phase than children who had received praise or no reward at all. Material rewards can undermine children’s intrinsic motivation to help.

Warneken, F., & Tomasello, M. (2008). Extrinsic rewards undermine altruistic tendencies in 20-month-olds. Developmental Psychology.

Treatment phase: No reward condition

Test phase: Child helps

Treatment phase: Praise condition

Test phase: Child does not help

Treatment phase: Material reward condition

Helping in children and chimpanzees: The role of rewards and costs

These video clips show examples from three experiments with 18-month-old children and semi-free ranging chimpanzees. We found that both chimpanzees and human children helped altruistically, regardless of any expectation of reward (Experiment 1). They continued to help even when helping was made more effortful in that chimpanzees had to climb up into a raceway and children had to surmount an array of obstacles in order to help (Experiment 2). Furthermore, chimpanzees helped other conspecifics: When one individual was unsuccessfully trying to open a door which was blocked by a chain, the other individual helped by releasing the chain (Experiment 3).

Warneken et al. (2007). Spontaneous altruism by chimpanzees and young children. PLOS Biology.

Exp1: Child in condition Reaching/No Reward

Exp2: Child in condition Reaching

Exp1: Chimpanzee in condition Reaching/No reward

Exp2: Chimpanzee in condition No Reaching

Exp3: Chimpanzee helps in experimental condition

Do children share resources based on merit?

How do children share rewards after one person has worked more than the other? In this study, 3- and  5-year-old children played a fishing game with a puppet partner in which they both collected coins. Children either collected fewer or more coins than their partner. They could then divide sticker rewards between themselves and their partner. When children had collected more coins in the fishing game, they allocated more rewards to themselves than the partner. By contrast, when the partner had collected more, they divided up the rewards equally. These result shows that at 3 years of age, children already consider merit when sharing resources, but they do so in a biased manner as they value their own work contribution more than that of the partner. 

Kanngiesser & Warneken (2012). Young children consider merit when sharing resources with others. PLOS ONE.

Child and puppet partner play fishing game

Experimenter explains sharing task

Child gives more to self than partner

Child gives more to partner than self

Proactive helping in children

Will children help others who aren’t even aware that a problem has occurred? We found that starting at 2 years of age, children would help proactively without any prompts or requests from the person needing help. When an accident had occurred without the person even knowing, children would offer their help proactively. 

Warneken (2013). Young children proactively remedy unnoticed accidents. Cognition.

Child helps by placing dropped can on the table

Child helps by handing dropped can to the experimenter

Child helps and comments on the situation

How children intervene against unfairness

Punishing others’ selfish behavior plays a key role in promoting cooperation. In our study, children could intervene against unfair sharing in ingroup and outgroup contexts. 6-year-olds showed ingroup favoritism when intervening against unfairness. However, 8-year-olds acted with less bias, indicating that ingroup favoritism influences human’s fairness behavior, but can be partially overcome with age.

Jordan, McAuliffe, & Warneken (2014). Development of in-group favoritism in children’s third-party punishment of selfishness. PNAS.

Children’s fairness behaviors across the globe

We were interested to learn how children’s sense of fairness develops across cultural groups. All children happily accepted when resources were shared equally. When a peer received more than the self, already young children rejected such distributions (so-called disadvantageous inequity). However, around school-age, many children also rejected allocations that would result in more candy for the self than the peer (advantageous inequity aversion).

^Blake, P. R., ^McAuliffe, K., Callaghan, T., Corbit, J., Barry, O., Bowie, A., Greaves, R., Kleutsch, L., Kramer, K., Ross, E., Vongsachang, H., Wrangham, R., & Warneken, F. (2015). The ontogeny of fairness in seven societies. Nature.

Child accepts an advantageous allocation

Child rejects an advantageous allocation

Child accepts a disadvantageous allocation

Child rejects a disadvantageous allocation

Children trade off costs and benefits for self and others

In this study, we investigated how children delay reward when there is a trade-off between waiting time and the size of the reward. We compared an individual context where the reward is for the child versus a context where the reward is for a peer.

Liu, Gonzalez, & Warneken (2018). Worth the wait: Children trade off delay and reward in self‐ and other‐benefiting decisions. Developmental Science.

This webpage is sponsored by the National Science Foundation