These experiments suggest a lot about kids’ social impulses when they’re not influenced by surrounding factors, which is both a strength and a weakness of the study. “Every individual is walking through this world with these competing motivations”—whether to be dominant or cooperative, for example—“and which takes precedence over the other is going to depend on the context,” said Meredith Martin, an assistant professor in educational psychology at the University of Nebraska-Lincoln who studies how children and adolescents deal with interpersonal relationships and bullying.

This may help inform efforts to combat phenomena such as bullying by showing how developmental factors and a child’s history influence those tendencies, minus all the contextual stuff happening in the given moment. At the same time, she continued, “It’s really hard to take the adolescent out of that context and understand how this would play out in bullying. Bullying is by its very nature a social phenomenon.”

Marjorie Martin, who’s taught elementary school for three decades, most of them in second grade but some of them with 3-year-olds, was even more skeptical. “I know that, generally, people think that [children] don’t really start to feel that inequality until they’re a little bit older, but in my experience the 3-year-olds and 4-year-olds want everyone to be happy,” she said, noting that she’s always taught in a private-school setting.

Marjorie (who isn’t related to Meredith) also emphasized that the experiments involved made-up individuals; if Léo and Nico were real, maybe the children would’ve reacted differently. “Even if you want to argue that their sense of reality is not fully formed at 3 years old, I still think they understand that they’re puppets,” she said. “They understand they’re not really hurting anybody’s feelings.”

Still, the findings contribute significantly the field of existing research, in which some studies suggest that children of all ages, even infants, favor equality, while others find that children actually tend to perpetuate inequality. What’s probably most noteworthy about this and similar studies is what they can illuminate about kids’ trajectory through school.

For one, they consistently point to age 8 as a developmental milestone. That’s when feelings of empathy—what the researchers in the latest study describe as a “vigilance for antisocial behavior”—really start to solidify. In the two experiments described in the new study, for example, the 8-year-olds likely evaluated what the dominant individual was doing and associated negative emotions with him, like guilt and sadness. The preschoolers, on the other hand, may have assessed the situations based on the outcome and associated the dominant figure with positive emotions like success.

Another study, titled “‘I had so much it didn’t seem fair’: Eight-year-olds reject two forms of inequity,” found that 8-year-old children frequently rejected unequal offers of candy even when that meant they themselves were the one who got the bigger share. The 4-to-7-year-olds almost never did. It’s also around age 8, according to the University of Nebraska’s Meredith Martin, when kids transition from using aggressive behavior to gain resource control—whether that resource be a toy or a child’s place in line—to more sophisticated, “prosocial” behavior. “What I see in kids that age is that they come up with more clever ways of gaining control, like, ‘Here, let me show you how to use that toy better,’” she said. It’s no coincidence that educators often describe third grade, which in the U.S. typically coincides with age 8, as the most important year in an individual’s academic career: It’s when children stop learning to read and start reading to learn.