Issue 2 – Science Feature 2

Contributed by Dr. Katie Hoemann


No fair! How children understand and react to violations of fairness norms

Science spotlight on 2022 Best Dissertation in Affective Science Award winner Dr. Meltem Yucel


In the spirit of Northern Hemisphere summer, imagine the following scenario: Two children are playing on the beach, building sandcastles. One finds an extra bucket and shovel, giving her the ability to get more sand at a time and to create a bigger and more elaborate sandcastle. The other child protests: it’s not fair that he does not have extra tools. His sandcastle will be smaller or may take more time to build. It won’t be as fun.

This scenario is innocent enough, but it illustrates children’s sensitivity to (un)fair distributions of resources. It also provides a context for probing how children understand norms about fairness. We know that children care deeply about unfairness. However, we don’t know how they compare it to other types of norm violations. Is having better beach toys a worse offense than pushing someone into the water? Than wearing a swimsuit to school? 2022 Best Dissertation in Affective Science Award winner Dr. Meltem Yucel used scenarios like these to investigate children’s perceptions of fairness norms, how these perceptions change with age, and what role affect plays in their moralization.

Dr. Yucel started from the observation that young children already have a sophisticated understanding of different types of norms. For example, they know it is immoral to hit or push other people, and that moral norm violations like physically harming someone are much more serious offenses than conventional norm violations like dressing inappropriately or playing a game wrong (Smetana et al., 2018; Yucel et al., 2020). They also enforce norm violations to ensure fair treatment of others (Yucel & Vaish, 2018). However, little work has examined the extent to which affect is involved in processing norm violations and how early this begins.

To bridge this gap, Dr. Yucel showed videos of moral and conventional norm violations to 3-year-olds, 4-year-olds, and undergraduate students while measuring their physiological arousal via pupillometry. She found that even the youngest participants showed greater arousal when witnessing moral as opposed to nonmoral violations. Eye-tracking data also showed that participants of all age groups attended significantly more to the victim of the moral violation than to the person present during the nonmoral violation. This is the first evidence of affective differences that co-occur with, and may contribute to, the behavioral distinction that even young children make between moral and conventional norms (Yucel et al., 2020).

Building on these findings, Dr. Yucel next conducted a series of five studies examining how children and adults perceive fairness violations. Overall, she found a meaningful developmental shift in children’s understanding of fairness. In one study (Yucel et al., 2022), 4-, 6-, and 8-year-old children saw pictures of moral violations (e.g., pushing someone), conventional violations (e.g., wearing inappropriate clothing), fairness violations (e.g., taking more toys), and control actions (e.g., asking permission) and indicated how ‘nice’ or ‘bad’ each action was. The 4-year-olds rated fairness and conventional violations similarly, while the two older groups rated fairness violations to be more serious. Critically, no age group perceived fairness violations to be as serious as moral violations. Dr. Yucel proposes that this is because the impact of unfair distributions is indirect and less perceptible, making them appear relatively harmless to children (see also Ball et al., 2017).

Understanding the development of fairness norms is important because the way we conceptualize unfairness changes how we respond to it. If we see unfairness as a moral norm violation (e.g., physical harm), we are more likely to intervene. If we see it more like a conventional norm violation (e.g., dressing inappropriately), we may still respond negatively but be less concerned about rectifying the imbalance. Consider our two children on the beach. The impact of beach toys on sandcastle size is admittedly trivial, but it is not hard to see how the same inequities unfold on a much larger scale.

Dr. Yucel’s findings carry a powerful message: resource inequality may be widely accepted in many societies because the harm it causes is less obvious than other moral violations. Encouragingly, however, they also sketch a path forward. They suggest that making the damage caused by unfairness explicit can shape the developmental trajectory of fairness norms. This has impacts for caregivers and teachers alike. As scientists, we can help parents be more aware of how they talk about unfairness at home, and we can help teachers socialize fairness concerns through tailored school curricula – in both contexts encouraging children to spontaneously consider the consequences of unfairness and how they can be addressed. Together, we can work to create a world centered on sharing and cooperation.



Ball, C. L., Smetana, J. G., & Sturge‐Apple, M. L. (2017). Following my head and my heart: Integrating preschoolers’ empathy, theory of mind, and moral judgments. Child Development, 88(2), 597–611.

Smetana, J. G., Ball, C. L., Jambon, M., & Yoo, H. N. (2018). Are young children’s preferences and evaluations of moral and conventional transgressors associated with domain distinctions in judgments? Journal of Experimental Child Psychology, 173, 284–303.

Yucel, M., Drell, M. B., Jaswal, V. K., & Vaish, A. (2022). Young children do not perceive distributional fairness as a moral norm. Developmental Psychology, 58(6), 1103–1113.

Yucel, M., Hepach, R., & Vaish, A. (2020). Young children and adults show differential arousal to moral and conventional transgressions. Frontiers in Psychology, 11, 548.

Yucel, M., & Vaish, A. (2018). Young children tattle to enforce moral norms. Social Development, 27(4), 924–936.