Social signature in an online environment: stability and cognitive limits
Social tie maintenance has always had cognitive and emotional costs and has always been leading to uneven distribution of communication volume among egos' alters. This distribution, known as a social signature, is assumed to be relatively stable for each individual. Availability of digital traces of human communication allows testing
whether this assumption is true and whether it holds in specific channels of computer-mediated communication. In this paper, we investigate private messaging on a popular social networking website using a sample of 39
egos and 8063 alters over the period of 18 months. We find that this channel of communication does not reduce cognitive costs as the overall number of users' active contacts, on average, does not differ from the cognitive limit known as Dunbar's number. Confirming some previous research, we also find that the volume of communication is unevenly distributed, related to emotional closeness, and that changes in this distribution (that is, the changes in social signature) over time within an individual are smaller than the distances between social signatures of
different individuals. However, as an absolutely novel finding, we demonstrate that the changes within individuals are statistically significant, thus questioning the concept of social signature as a stable phenomenon.