Swarm intelligence

The same problem, solved without a central search. Hundreds of simple agents move through the space of possible answers at once, each remembering its own best find and signalling it to the rest, and the group converges on the promising region. Bird flocks and ant colonies are the model, and the behaviour is genuinely borrowed rather than a metaphor.

Used where evolutionary methods are used, with a different trade-off: faster to converge, and more prone to settling early on something merely good.