Presence of homophily in the communication patterns of areas. The x-axis denotes the happiness levels of areas receiving calls and the y-axis denotes the sum of aggregate calls. (a) Interaction plot. The black dotted line indicates the happy areas that place the calls while the red solid line indicates the unhappy areas that place the calls. (b) Another way of visualizing the results. The dark color represents the happy areas that place the calls, while the light color represents the unhappy areas that place the calls.