What roles do uncertainty, surprise, and arousal play in infants’ curiosity?

International audience ; How do uncertainty and surprise shape curiosity in infants? Pioneering studies showed that 8-month-old infants are more curious about information that is neither too certain nor too uncertain, an adaptive phenomenon known as the "Goldilocks effect" that maximizes the cost-to-benefit ratio in information acquisition (Kidd et al., 2012, 2014). However, several questions remain. First, since these studies indexed curiosity via infants’ gaze, it remains unclear whether the Goldilocks effect generalizes to engaging contexts such as problem-solving tasks in which curiosity is central (Modirshanechi et al., 2023). Second, while surprise is known to influence curiosity (Murayama et al., 2019), it is unknown whether moderate surprise elicits the strongest curiosity in infants, as does moderate uncertainty. We thus tested 60 infants aged 18–24 months in a task where an experimenter pressed the top button of a demonstration cube eight times, triggering a sequence of sounds. The cube was then handed back to the infant, now silent. This procedure was repeated with four cubes, each emitting the sequence of sounds with varying probabilities (0, 1, 4, or 8 out of 8 presses) to manipulate uncertainty. We assessed curiosity via exploratory (e.g., varied button presses) and exploitative behaviors (e.g., repeated pressing) (Berlyne, 1966). Additionally, we developed an algorithm to detect the facial expression of surprise in infants (i.e., raised eyebrows, open eyes, open mouth; Camras et al., 2002). In line with the Goldilocks effect, we predicted that infants would show greater exploration - and hence greater curiosity - when interacting with the cube of intermediate uncertainty than with the cubes producing certain or uncertain outcomes. Furthermore, since Berlyne (1972) speculated that excessive surprise is aversive, we predicted that the most curious infants would exhibit a moderate expression of surprise. Behavioral and statistical analyses are on their way, with half of the infants tested.