With the advent of ubiquitous computing, interaction design has broadened its object of inquiry into how smart computational artifacts inconspicuously act in people's everyday lives. Although user-centered design approaches remains useful for exploring how people cope with interactive systems, they cannot explain how this new breed of artifacts participates in people's sociality. User-centered design approach assumes that humans control interactive systems, disregarding the agency of smart artifacts. Based on Actor-Network Theory, this research recognizes that artifacts and humans share the capacity of influencing society and meshing with each other, constituting hybrid social actors. From that standpoint, the research offers a triadic structure of networked social interaction as a methodological basis to investigate how smart devices perceive their social setting and adaptively mediate people's interactions within activities. These triadic units of analysis account for the interactions within and between human-nonhuman collectives in the actor-network. The "within interactions" are those that hold together humans and smart artifacts inside a collective and put forward the collective's assembled meaning for other actors in the network. The "between interactions" are those that occur among collectives and characterize the dominant relational model of the actor-network. This triadic approach was modeled and used to analyze the interactions of participants in three empirical studies of social activities with communal goals, each mediated by a smart artifact that enacted--signified--a balanced distribution of obligations and privileges among subjects. Overall, the studies found that actor-networks exhibit a social viscosity that hinders people's interactions. This is because when people try to collectively accomplish goals, they offer resistance to one another. The studies also show that the intervention of smart artifacts can facilitate the achievement of cooperative and collaborative interaction between actors when the artifacts enact the dominant moral principles which prompt the "preservation of social balance," enhance the network's "information integrity," and are located at the "focus of activity." The articulation of Actor-Network Theory principles with interaction design methods opens up the traditional user-artifact dyad towards triadic collective enactments by embracing diverse kinds of participants and practices, thus facilitating the design of enhanced sociality. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]