Third-party punishment by preverbal infants

Third-party punishment of antisocial others is unique to humans and seems to be universal across cultures. However, its emergence in ontogeny remains unknown. We developed a participatory cognitive paradigm using gaze-contingency techniques, in which infants can use their gaze to affect agents displayed on a monitor. In this paradigm, fixation on an agent triggers the event of a stone crushing the agent. Throughout five experiments (total N = 120), we show that eight-month-old infants punished antisocial others. Specifically, infants increased their selective looks at the aggressor after watching aggressive interactions. Additionally, three control experiments excluded alternative interpretations of their selective gaze, suggesting that punishment-related decision-making influenced looking behaviour. These findings indicate that a disposition for third-party punishment of antisocial others emerges in early infancy and emphasize the importance of third-party punishment for human cooperation. This behavioural tendency may be a human trait acquired over the course of evolution. Using a participatory cognitive paradigm based on gaze contingency, Kanakogi et al. show that eight-month-olds increased their selective gaze to antisocial others to punish them, suggesting that preverbal infants engage in third-party punishment.

Automated summary

This study reveals that eight-month-old infants engage in third-party punishment towards antisocial others, indicating that this behavioral tendency may be acquired by humans during early infancy.