Individual differences in processing speed and curiosity explain infant habituation and dishabituation performance

Habituation and dishabituation are the most prevalent measures of infant cognitive abilities, and they have reliably been shown to predict later cognitive functioning. Yet, the exact cognitive processes that underlie them are still unknown. To shed light on the cognitive factors that underlie infant habituation and dishabituation, we tested 164 8-month-old infants on a classic habituation task and a novel visual learning task. We used a hierarchical Bayesian model to identify individual differences in sustained attention, learning performance, processing speed, and curiosity from the visual learning task. These factors were then related to habituation and dishabituation. We found that habituation time was related to individual differences in processing speed, while dishabituation was related to curiosity, but only for infants who did not habituate. These results offer novel insights into the mechanisms underlying habituation and serve as proof of concept for hierarchical models as an effective tool to measure individual differences in infant cognitive functioning.