This chapter reviews socio-cultural theories of the origins self-reflection. Four types of theory can be distinguished: rupture theories, mirror theories, conflict theories, and internalization theories. In order to address the limitations of these theories, Mead's theory of the social act is advanced. These theories are evaluated against an empirical instance of self-reflection and a novel conception of complex semiotic systems is proposed. Mead's theory of the social act is a theory of institutional structures. Additional social acts in which frequent position exchange occurs include: buying/ selling, giving/receiving, suffering/helping, grieving/consoling, teaching/learning, ordering/ obeying, winning/losing, and stealing/ punishing. The social act is the institution that first provides individuals with roughly equivalent actor and observer experiences, and second, integrates these perspectives within the minds of individuals. The chapter explains the semiotic conditions underlying any self-reflection in terms of the structure of the sign, or significant symbol.