Fig 3. Spatial and temporal dynamics of a collective U-turn for N = 2.

(A) Individual fish trajectories in the tank during the U-turn. Each individual is represented by a unique color. The temporal sequence is indicated by circles equally spaced over time with a time-step of 0.04 s (empty circles) and 0.1 s (filled circles). Arrows denote direction of motion. Grey wide line is the tank’s border. (B) Group polarization P(t), with a minimum value P_min ≈ 0.27 reached at t ≈ 0.46 s. (C) Sine of the angle of incidence of fish to the wall: when parallel to the wall, sin(θ_w) = 1 (anti-clockwise direction) or sin(θ_w) = −1 (clockwise). The three vertical lines of each color indicate for each fish the beginning, the middle and the end of its U-turn, with the middle representing the time when a fish has finally reversed its original direction. (D) Interaction with influential neighbors: arrows point from influential neighbors to the focal fish and with the same color as the focal fish. (E) Fish bursting activity and their influential neighbors. Dots at i = 1, 2 correspond to bursting activity, blank corresponds to coasting. Dots at i − 0.5 represent bursting activity of the neighbor influencing fish i.