| Contents |
| Social connectivity is the key process that characterizes the structural properties of social networks and in turn processes such as navigation, influence or information diffusion. Since time, attention and cognition are inelastic resources, humans should have a predefined strategy to manage their social interactions over time. However, the limited observational length of existing human interaction datasets, together with the bursty nature of dyadic communications have hampered the observation of tie dynamics in social networks. Here we develop a method for the detection of tie activation/deactivation, and apply it to a large longitudinal, cross-sectional communication dataset ($\approx$ 19 months, $\approx$ 20 million people). Contrary to the perception of ever-growing connectivity, we observe that individuals exhibit a finite communication capacity, which limits the number of ties they can maintain active. In particular we find that men have an overall higher communication capacity than women and that this capacity decrease gradually for both sexes over the lifespan of individuals (16-70 years). We are then able to separate communication capacity from communication activity, revealing a diverse range of tie activation patterns, from stable to exploratory: humans manage their interactions so that the number of open connections is kept constant through time and thus some individuals are {\em social keepers} (they maintain a clustered static network around them), other seem to undergo a {\em social exploring} strategy (in which many ties are formed and destroyed in time. Finally, we use computer simulations to investigate the possibility that social explorers have a competitive advantage towards information awareness because of their fast and distant tie formation dynamics. Counterintuitively, we found that social keepers receive information before social explorers do. The answer to this paradox is that, despite having a large variability in the social structure around a social explorer, the amount of time allocated to their contacts is low enough to produce countervailing effects and hinder information diffusion. |
|