Part of the problem, some experts now believe, is that artifi cial brains have been designed without much attention to real ones. Pioneers of artifi cial intelligence approached thinking the way that aeronautical engineers approached fl ying without much learning from birds. It has turned out, though, that the secrets about how living brains work may offer the best guide to engineering the artifi cial variety. Discovering those secrets by reverse-engineering the brain promises enormous opportunities for reproducing intelligence the way assembly lines spit out cars or computers.