Eighteen-month-olds infants are aroused and concerned by moral transgressions
Our study, accepted for publication in Proceedings of the National Academy of Sciences of the United States of America (PNAS), found that human infants are physiologically aroused (measured by changes in pupil size) and empathically concerned (measured by expressive behaviors) when observing someone who destroys another person’s picture which would make the owner sad. Importantly, infants did not show such enhanced physiological or empathic reactions when witnessing a harmless violation (i.e., someone uses a wrong tool to follow instructions to destroy a picture), suggesting that already very young children differentiate between prototypical moral (harmful) and conventional (harmless) transgressions. This study used multiple methods (eye-tracking and observations of expressive behaviors) to investigate the roots of human moral cognition. All infants watched the exact same video clip, but based on verbal interactions, the act of destroying a picture was either a conventional (using wrong tool) or a moral (producing harm) transgression. Infants autonomously inferred harm in the moral context and their arousal and expressive behaviors bespeak the notion that they responded with empathic concern for the victim. Overall, this study is among the first to suggest that during the second year of life, infants understand something about distinctively moral actions and that their moral development is fostered by both social-cognitive and socio-affective processes.