Human minds construct cultural products that form part of the environmental niche to which new generations  of human minds must adapt. A remarkable feature of cultural transmission is that infants fast-learn a vast amount of cultural skills very early on even when they cannot yet fully grasp their relevant causal, functional, intentional, or adaptive properties. This represents an apparent paradox: how can such cognitively ‘opaque’ cultural forms be successfully transmitted and maintained across generations? Are there specialized cognitive mechanisms evolved to make efficient intergenerational transfer of such cultural knowledge possible?

The dominant view holds that it is the capacity for imitative learning that serves the evolutionary function of cultural transmission in humans. I’ll argue, however, that presently proposed models of imitative learning face the problem of ‘relevance-blindness’  as they lack appropriate  selection mechanisms to differentiate relevant (to be re-enacted and learned) from non-relevant, incidental to be disregarded) aspects of observed behaviors. ‘Relevance-blind’ imitative copying would be a wasteful and inefficient transmission mechanism likely to lead to distorted reproduction and eventual extinction of useful cultural innovations over the generations.

I’ll suggest that the emergence of cognitively opaque cultural skills during hominin evolution and the consequent need for their efficient intergenerational transmission created evolutionary pressure leading to the selection of a new type of  ‘relevance-guided’ social-communicative learning mechanism of mutual design: the system of ‘Natural Pedagogy’ (NP) (Gergely & Csibra, 2006). On the naïve “teacher’s” side, NP involves an instinctual inclination to ostensively manifest - and guide the ignorant “learner’s” inferences to identify – relevant cultural information to be fast-learned. On the naïve “learner’s” side, NP involves evolved sensitivity to ‘ostensive’ (e.g., eye-contact, contingent reactivity, or infant-directed speech) and referential (e.g., gaze-shift or pointing) cues that  are interpreted to signal the other’s communicative intention to manifest new, relevant (and generalizable) cultural knowledge about a referent (and its kind). Such cues trigger a receptive learning attitude to fast-learn ostensively manifested  contents even  when they  are cognitively opaque to the learner. I’ll present evidence to support the NP hypothesis from our infancy studies testing the basic assumptions of the theory about the nature of early cultural learning in humans in a number of different knowledge domains.