Understanding relations between the social and cognitive contributions to thinking and acting has become a pressing goal for psychological theorizing. Central to understanding these relations is the negotiation and construction of knowledge that is comprised of the inter-psychological processes that engage both cognitive and social experiences. This paper proposes that these processes can be understood through a complex of relations among different sociogenetic sources and between those sources and individuals' agency as constituted by their life histories or ontogenies. Rather than a single sociogenetic source, the social contributions are held to have historical-cultural and situational geneses. However, through inter-psychological processes these contributions are mediated by individuals' unique and socially shaped cognitive experiences. Findings from an investigation of the same vocational practice (hairdressing) conducted in four different work settings are used to identify tentative relations between the sociogeneses of the goal-directed activities that individuals engage in, and how these individuals represent their knowledge in memory. Together, these findings tentatively elaborate particular sociogenetic contributions to individuals' thinking and acting, and relations between particular elements and phases of goal-directed activities and, hence, their impact on cognitive change (development).