Abstract
Curiosity-driven information seeking is a crucial behaviour thought to drive our progress as a species. Valuing information as rewarding has been established as a driver of curiosity in human adults and non-human primates, characterised by a stringent set of three criteria formalized by work in primates, but direct evidence in human infants remains absent. We followed N=125 infants longitudinally over three visits (12, 18, 24 months) and used an infant-controlled eye-tracking paradigm to test whether valuing information as rewarding could also underlie curiosity in infancy. In each trial, infants could reveal two hidden characters by looking at their hiding locations, yielding either high or low information-gain. Revealing the first character was coupled with a rewarding animation, while revealing the second character required to disengage and thereby trade-off the ongoing animation for information. We found evidence in support of all three curiosity criteria: throughout their second year of life, infants were willing to forego extrinsic rewards to obtain information , even when the information was strategically useless, and – from 18 months – in a way that scaled with information gain. Infants did not meet the third criterion at the youngest age, which we attribute to age-related cognitive-load effects. Individual differences in infants' sensitivity to information gain showed modest stability across the visits. Overall, this study establishes reward-based information-seeking as a conserved mechanism present from early infancy, with early individual differences that may carry lasting consequences for learning and cognitive development.