Fig. 4

a Models are based on the vertical visual occupancy casted by neighbors on the retina of the focal fish and the algorithms and response functions extracted from VR experiments (Eq. ¹ and “Methods”). Left: Each neighbor is represented by its estimated vertical size at specific visual angels. Middle: The vertical sizes casted by neighbors elicit a turning bias based on the age dependent response functions observed in VR experiments p(turnright∣vi). Right: The turning biases are then averaged on each side (yellow bars) and compared between the eyes to elicit a turing probability p(turnright) (black bar) for the next bout performed by the fish (“Methods”). b Examples of simulated trajectories for 7, 14, and 21 dpf larvae in arena sizes that match real group experiments. c Left: Normalized dispersion values for one simulated group of 5 fish at 7 dpf, with and without social interactions. Zero represents the expected average dispersion when fish do not interact, and positive values represent overdispersed distributions (“Methods”). Right: Simulated groups of 5 fish at 7 dpf modeled with social interactions show higher dispersion levels than chance and are also more dispersed than simulated groups modeled without social interactions. Bars represent means; error bars are SEM (N = 50 simulations). Experimental data of fish swimming in the light and in the dark is plotted for comparison (same as Fig. 1c). d Same as in (c), only for simulations of different age groups. Simulated groups switch from overdispersed to clustered groups from 7 to 21 dpf. Experimental data of different age groups is plotted for comparison (same as Fig. 1d). e Probability to turn right as a function of the difference in total angular occupancy experienced by each eye (negative values - higher occupancy to the left) in the simulations. (Similar to Fig. 1e, f for group experiments). Bold lines represent turning probability calculated as the fraction of right turns out of all turns collected from all simulated fish in 5^o bins; error bars are the 95% confidence interval of the fitted Binomial distribution to the events in each bin.