Social Networks and Human Communication Patterns
In an age of ubiquitous and aggressively expanding communication, where a great deal of emphasis is placed on expanding via technology our capability to engage with more and more things (people, news, marketing), we are not yet sure what our innate limitations are. The fact that some individuals have thousands of Facebook friends might suggest that indeed technology is achieving what our own abilities do not allow us to do. But such claims seem to contradict a long line of research (e.g., BK, Dunbar) that suggests humans have inherent limits in their ability to engage in socially meaningful ways that cannot be easily bypassed. Furthermore, there is reason to believe our social ties are structured (layered).
While the current state of the discussion has placed a great deal of emphasis in static properties (maximum number, or layering of our contacts), it is far less clear what the dynamic (time-evolving) properties of human communication look like. The behavior of such properties is in fact critical to our understanding of the problem, because if it is true that ICT (information and communication technologies) can have an impact in our communication, then when faced with a disruption that could increase people's social network, one should be able to measure such change.
In my work together with Jari Saramäki, Robin Dunbar, Felix Reed-Tsochas, and others, we find evidence that in fact communication patterns have persistent properties when disturbed by outside influences. When faced with considerable changes to their social surroundings (e.g. moving to another city, changing jobs), individuals may replace those people (alters) they interact with, but tend to recreate with those new friends a similar communication pattern in terms of time or amount of communication that they had before the disturbance. It is also not true that by changing surroundings and meeting new people, they effectively increase their communication, because in order to allow new alters in, they reduce or may even drop contact with others. This effect keeps communication allocation effort roughly persistent while allowing social turnover.
We call those communication patterns social signatures because they also seem to be specific to each individual (my social signature is not like yours. See this video). This work has led to some media attention that has interpreted the work with a "one-in one-out rule", meaning that when one of our friends drops out of our communication pattern, another one takes her/his place receiving a similar amount of communication as the one that left.
Some relevant publications:
Building social signatures: (A and B) Social signatures are constructed for each ego by counting the number of calls to each of his or her alters, ranking the alters based on this number, and then calculating the fraction of calls to the alter of each rank.
Examples of persistent social signatures of two egos over time: Upper (A–C) and Lower (D–F) depict the time evolution of the social signatures of two different male participants who both moved to another city to attend university while the study was ongoing. The symbols correspond to alters observed for the first time in intervals I1 (circles), I2(squares), and I3 (diamonds) or to kin (triangles) as reported by the egos. The large turnover in the networks of the participants is clearly visible. The dashed line indicates the social signature averaged over all 24 egos. In the social signatures depicted in A–C, two kin alters receive a higher-than-average fraction of outbound calls, whereas the signatures D–F do not deviate much from the average. Note the similarity of social signatures along the horizontal direction signalling that a given ego has roughly constant patterns of contact even under social turnover (persistence).
Figures taken from "Persistence of Social Signatures in Human Communication"