Programming makes up a relatively small amount of the effort in a mass market game. Most of the development time goes into content creation, making models, textures, environments, sounds, music, and animation—everything from the concept art to the detailed level design.
Over the last decade developers have reduced the programming effort further by reusing their technology on multiple titles, putting together a game engine on which several titles can run. Adding a comprehensive suite of AI to the engine is only its latest iteration.
Most developers aren’t content to stop there, however. Because the effort involved ...