Culture has become a critical concept for social psychology over the past quarter of a century. Yet, cultural dynamics, the process and mechanism of formation, maintenance, and transformation of culture, has begun to be investigated only recently. This article reports the current state of play of a research program that takes cultural dynamics as its central question. In this approach, humans are construed as meaning making animals that create, recreate, and exchange information, and turn it into a meaningful basis for action. The locus of meaning making and remaking is an everyday joint activity. The grounding model of cultural transmission describes how cultural information is deliberately or inadvertently transmitted in a joint activity. As we go about our business of living our daily lives, we ground information to our common ground, and construct a social reality that is mutually meaningful and yet only local. If locally grounded information is further generalized to a large collective and disseminated through social networks, repeated and iterative activations of the grounding process maintain the social reality of the collective that we take for granted. Implications of the grounding model of cultural transmission and future research directions are discussed.