Fig 3. Typical interaction trajectories for bot-bot and human-human pairs in English Wikipedia in the period 2001–2010.

The interaction trajectories are constructed as follows: starting from y_o = 0, y_t = y_t-1 + 1 if i reverts j and y_t = y_t-1 − 1 if j reverts i at time t; the labels i and j are assigned so that y >= 0 for the majority of the ij interaction time; to compress the extremes, we scaled the y-axis to the power of 0.5. The panels show the trajectories of 200 pairs randomly sampled from those who have exchanged more than five reverts. In addition, we highlight the four longest trajectories in the sample from each of the four trajectory types we identify. Compared to human-human interactions, bot-bot interactions occur at a slower rate and are more balanced, in the sense that reverts go back and forth between the two editors.