As apparent from Fig. , the collective processes lead to a consistent increase in the simulated diffusivity. This increase applies globally, i.e. it is roughly similar over the entire studied island size range. The additional processes do thus not affect the pronounced non-monotonous behavior in the nonscalable regime up to N ≈ 100 , nor the close-to-one exponential size scaling for larger islands (D N ∝ N -β , β = 1.02 ± 0.05 and 0.95 ± 0.05 for the APE and humanintuition models, respectively, cf. Fig. ). The oscillation in diffusivity with island size is well observed in other computational studies and arises from the pronounced stability of islands with perfect square or nearsquare rectangular ground-state shape at T = 0 K (N = n 2 or n × (n + 1)) . Further sensitivity analysis regarding the individual impact of these collective processes is provided in the SI. Overall, these findings are thus perfectly consistent with the effect of other collective diffusion mechanisms that had been proposed for island diffusion on coinage-metal fcc(111) and fcc(100) surfaces before . In the past though, such collective mechanisms have typically been identified through cost-intensive molecular dynamics simulations for smallest islands or clusters of atoms, whereas here they result automatically from the APE framework.