Figure 1

Reciprocal and non-reciprocal activity in empirical communication networks. (top) Schema for separating a temporal network of time-stamped, directed communication events between pairs of individuals (black arrows, left) into reciprocal and non-reciprocal components (right). A pair of consecutive events is a reciprocation if events have the opposite direction (blue areas), and a non-reciprocation if they have the same direction (red areas). (Non-) reciprocal time gaps are then the inter-event times within (non-) reciprocations (see Additional file 1 Section S1). (bottom) Complementary cumulative distribution function \(P(n' > n)\) (ccdf), the fraction of nodes having strictly more than n reciprocations (solid) or non-reciprocations (dashed) in various communication channels. one-to-one communication channels tend to be more reciprocal than broadcasting channels (i.e. Twitter; see Table 1)