In order to recognize the social capital formation, we first need to understand the process of social link formation, as network structures are the basis of social capital. Due to recently emerging social network services, such as Facebook, which facilitate and provide an online representation of our relationships, our social networks are composed by the interweaved online and offline networks and their components.
In our study, we quantitatively measure offline interactions and examine the corresponding evolution of online social network in order to understand the significance of interrelationship between online and offline social factors in generating social ties. We analyze the radio signal strength indicator sensor data from a series of social events to understand offline interactions among the participants and measure the structural attributes of their existing online Facebook social networks. By monitoring the changes in their online social networks before and after offline interactions in a series of social events, we verify that the ability to develop an offline interaction into an online friendship is tied to the number of social connections that participants previously had, while the presence of shared mutual friends between a pair of participants disrupts potential new connections within the pre-designed offline social events. Thus, while our integrative approach enables us to confirm the theory of preferential attachment in the process of network formation, the common neighbor theory is not supported.
Furthermore, we propose social potential model which considers the invisible, but invested resources such as offline interaction, as well as, preferential biases from preexisting online network characteristics to promote and create a social link between two individuals. The social potential perspective allows us to interpret the process of social link formation, as it breaks the process down to multiple components, which describes the accumulation of invested resources, the threshold for these resources to overcome and create a link, and social catalyst that lowers the threshold and promotes the linking process. By utilizing the offline social interaction networks of the participants attending a series of offline social events and their Facebook friendship networks prior to the events, we have designed a real-life multilayered network to validate our social potential model, calculating the interaction necessary to overcome the social threshold for link formation and identifying the social catalyst, brokerage, embedded in the prior network which permits the interaction to influence the link formation. Our social potential model allows us to dissect the process of social link formation which ultimately generate social network and the source of social capital.