One orange focal individual, rest of the group in green. Watch how its personal risk indicators fall as the group grows, from two independent mechanisms.
Per-individual vigilance time needed ("many eyes")100%
Per-individual capture probability (dilution)100%
Vigilance uses an illustrative 1/√N scaling (more eyes collectively watching, so each individual needs less); dilution uses exactly 1/N (a predator captures at most one individual per attack, so risk splits evenly across the group).