Michael Tomasello. Becoming Human: A Theory of Ontogeny
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«I wish to describe and explain the ontogeny of uniquely human psychology, using as a starting point great ape ontogeny. Great apes engage in basic processes of perception, memory, and categorization, as well as more complex processes of intentional communication, prosocial behavior, and social learning. From this starting point, we may then attempt to identify the unique aspects of human psychology as they emerge ontogenetically over the first years of life.

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Our specific proposal is that the ontogeny of human cognitive and social uniqueness is structured by the maturation of children’s capacities for shared intentionality. Mirroring the phylogenetic sequence, this maturational process unfolds in two basic steps: first is the emergence of joint intentionality at around nine months of age, and second is the emergence of collective intentionality at around three years of age.

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My attempt in what follows is to use this neo-Vygotskian framework to explain the origin and development of children’s species-unique forms of psychological functioning during the first six years of life.»