The effect of just these hitherto unconsidered collective processes on island diffusivity is illustrated next with two microkinetic models for lattice kMC simulations. The humanintuition model only considers the 149 surface hopping and exchange diffusion type processes a human researcher would likely have enumerated, whereas the APE model additionally considers the 55 collective processes. Both models are implemented in the lattice kMC code kmos3 to run kMC simulations for varying island sizes in the range 16 ≤ N ≤ 144 Pd atoms. Each simulation is performed in a (40 × 40) periodic boundary condition simulation cell containing one island as shown in Fig. , and we extract the diffusion coefficient D N from the migrating island center of mass position during one kMC trajectory. Convergence of D N to within ±5 % was generally reached in O(10 9 ) kMC steps. We note that the total number of kMC steps executed to obtain the data summarized in Fig. is thus O(10 11 ). In the above described EON akMC runs, the system evolved only over ∼ 80 -90 steps within the computational budget of 12000 TS searches spent for APE. This underscores the necessity to separate the process exploration from the actual microkinetic simulations to even only address systems of such moderate complexity.