Figure 2

Contour maps for the (a) average political position of the nearest-neighbor \(P^{\text{NN}}\) and (b) average leaning of tweets received, \(P^{\text{IN}}\) against the average political position of a user P. Colors represent the density of users: the lighter the larger the number of users. Probability distribution of P, \(P^{\text{NN}}\), and \(P^{\text{IN}}\) are plotted in the axes. Only users with activity \(a\ge10\) (corresponding to 14813 users) are considered