On Universality in Human Correspondence Activity

Abstract

Correspondence Communications Statistical physicists and social scientists have attempted to describe human activities, in terms of physical models, and look for universal principles. Correspondence patterns are thought to be driven primarily by the need to respond to other individuals with both e-mail and letter correspondence showing power-law distributions. Because there are different exponents for the two modes of correspondence, it has been suggested that human correspondence falls into one of two universality classes and that e-mail and letter correspondence are fundamentally different activities. Now Malmgren et al. (p. 1696 ) tested whether human correspondence patterns are instead driven by mechanisms such as circadian cycles, task repetition, and changing communication needs. Letter correspondence, like e-mail correspondence, was accurately modeled as a cascading nonhomogeneous Poisson process giving rise to non-Gaussian statistics, but not to power-law statistics. Instead, the correspondence patterns of each individual could be uniquely characterized by the parameters of the model; that is, the process was shown to be universal, but the parameters were not. Thus, an individual's affinity toward a particular life-style will affect communication patterns, which can be modeled as a complex system.