Figure 2.

Duration of succeeding call ( ${\mathit{T}}_{\mathit{i}\mathit{j}}$ ) as a function of the gap ( ${\mathit{\tau }}_{\mathit{i}\mathit{j}}$ ) for different ego-alter pairs belonging to $\mathcal{S}$ (set of regular contacts). The curves shown with different symbols are obtained by log-binning the actual data corresponding to the pairs. The age cohorts of the ego are provided in the figure legend of (a). The plots correspond to the different sexes of the ego and the alter: female-female (FF) (a), female-male (FM) (b), male-female (MF) (c) and male-male (MM) (d). The solid line corresponds to a regression fit of the form: $\beta log\tau +\alpha$, to the scatter corresponding the ego age cohort 35.