Abstract
Recent comparative findings by Lewis et al. (Lewis LS, Ritov O, Herrmann E, Reddy RB, Sanchez-Amaro A, Gopnik A, Engelmann JM. 2025 Chimpanzees and children are curious about social interactions. Proc. R. Soc. B. 292, 20242242.) reveal a shared drive in chimpanzees and children to seek information about third-party social interactions, even at a material cost. This commentary situates these results within a neurodevelopmental and evolutionary framework, proposing that social curiosity is a manifestation of a deeply conserved, motivationally driven system for social valuation centred on the medial prefrontal cortex (mPFC). We synthesize neuroimaging evidence showing selective engagement of mPFC while infants attend to third-party social interactions. We propose that the mPFC, as a primary valuation hub, guides the specialization of social perceptual regions over development. This framework interprets social curiosity as a high-level cognitive function driven by the mPFC, assigning intrinsic reward value to social information, consistent with the social information hypothesis. The willingness of older children to preferentially orient to and forgo a reward for social information can thus be understood as the behavioural output of a brain system calibrated from infancy to tag such information as intrinsically valuable.