Figure 7.

(a) The mean change in direction of motion, $(\mathrm{\Delta }\theta /\mathrm{\Delta }t)(x)$, of leaders (red curve) and followers (blue curve). In this plot, the focal individual is located at the origin, and is travelling parallel to the positive x-axis (from left to right). Positive changes in direction correspond to anticlockwise (or left) turns, and negative changes in direction correspond to clockwise (or right) turns. Details of (b–d) are the same as in figure 1.